Stimulant is a great idea.
Darkest Night and Radiation Infection are two of the few toggles that drop when mezzed, and both have non-trivial recharge. You wont want to use it all the time, but there will be cases where it will save your bacon, eg mezzing Elite bosses who you really want to keep Darkest Night on.
I had a lot of fun hero-side with a Fire/Energy blaster and Dark/Rad Blast Defender, thers a certain overlap here that suggests that this pairing should work well.
Check out the dual-boxing link in my sig for some binds and software to help control two
characters, by the way.
BTW I've found Sonic Resonance to be a great back-seat set - the only power requiring a mouse click is Liquefy. Pairing with a brute... nice! 
Thanks, I also appreciate the guide. The duo is doing quite well so far. Stimulant has defnitely been a lifesaver. Once I pick up Stamina I think this should really take off.
I've been kicking around the idea of dual-boxing and decided to give it a shot recently. After thinking about strategies, I decided to give a few different pairs a try: a Stone/Fire brute and Dark/Sonic corruptor (which are moving along very nicely) and a Rad/Dark corruptor and a Fire/Rad corruptor. Since corruptors tend to be a little squishy (my first 50 was a Rad/Rad corruptor), I thought it might be worthwhile to see if anyone saw any glaring weaknesses in the builds below (individually or with respect to team synergy).
Since I'm still getting used to controlling two characters simultaneously, I tend to lead with one and keep the other in follow mode. The Rad/Dark is my leader because Dark Miasma tends to require a little more clicking than Radiation Emission and I tend to start with the Radiation Blast attacks to wear spawns down then use the Fire AoEs to finish them off (so far, firing off Irradiate, Rain of Fire, and Fireball on a Tar Patch is pretty much an "I Win" button).
My major questions are how well should I expect this pairing to hold up as the enemies get stronger and start to mez on a regular basis? Is Stimulant (from the Medicine pool) a reasonable (if not perfect) source of mez protection?
Both characters are currently Level 9. I tend to start battles by picking a target (boss or lieutenant) and activating Darkest Night and Radiation Infection simultaneously. (I've been able to do this to bosses and take my time picking off the minions and lieutenants while the boss keeps missing. Long run, I expect to use lieutenants as my primary anchor in order to prioritize killing the bosses first.) Once I have Fearsome Stare I suspect I will lead with that (followed by Radiation Infection, Darkest Night, and Tar Patch).
Don't take the slotting too seriously, most of them are just indicators of the direction I intend to take without delving into set bonuses. I don't have that much infamy, so I'll have to figure out set IOs as I move along.
+----------------------------------------------------------------
+ Built with SuckerPunch's Online Planner v5.0
+ http://planner.cohtitan.com/planner
+----------------------------------------------------------------
Archetype: Corruptor
Primary: Radiation Blast
Secondary: Dark Miasma
+----------------------------------------------------------------
01: X-Ray Beam => Accuracy(1), Accuracy(3), Damage(7)
01: Twilight Grasp => Accuracy(1), Accuracy(3), Heal(9), Heal(13), Recharge(15)
02: Neutrino Bolt => Accuracy(2), Accuracy(5), Damage(17), Damage(34)
04: Darkest Night => EnduranceDiscount(4), Debuff_ToHit(5), Debuff_ToHit(9), Debuff_ToHit(17)
06: Irradiate => Accuracy(6), Accuracy(7), Damage(11), Damage(13), EnduranceDiscount(34)
08: Tar Patch => Recharge(8), Recharge(34), Recharge(43)
10: Recall Friend => EnduranceDiscount(10)
12: Stimulant => Interrupt(12)
14: Swift => SpeedRunning(14)
16: Health => Heal(16), Heal(46), Heal(46)
18: Cosmic Burst => Accuracy(18), Accuracy(19), Damage(19), Damage(25), EnduranceDiscount(25)
20: Stamina => Recovery(20), Recovery(21), Recovery(21)
22: Fearsome Stare => Accuracy(22), Accuracy(23), Debuff_ToHit(23), Debuff_ToHit(27), Empty(29), Empty(33)
24: Shadow Fall => EnduranceDiscount(24), Buff_Defense(40), Res_Damage(40), Res_Damage(43), Res_Damage(43)
26: Neutron Bomb => Accuracy(26), Accuracy(27), Damage(27), Damage(29), EnduranceDiscount(31)
28: Petrifying Gaze => Accuracy(28), Accuracy(29), Hold(31), Hold(31)
30: Howling Twilight => Recharge(30), Stunned(33), Recharge(37), Recharge(37)
32: Atomic Blast => Accuracy(32), Accuracy(33), Damage(45), Damage(46)
35: Proton Volley => Accuracy(35), Accuracy(36), Damage(36), Interrupt(36), Damage(37)
38: Dark Servant => EnduranceDiscount(38), Accuracy(39), Debuff_ToHit(39), Hold(39), Immobilized(40)
41: Soul Drain => Accuracy(41), Accuracy(42), Buff_ToHit(42), Buff_ToHit(42)
44: Power Boost => Recharge(44), Recharge(45), Recharge(45)
47: Dark Embrace => EnduranceDiscount(47), Res_Damage(48), Res_Damage(48), Res_Damage(48)
49: Soul Storm => Accuracy(49), Accuracy(50), Hold(50), Hold(50)
+----------------------------------------------------------------
+ Inherent Powers
+----------------------------------------------------------------
01: Brawl => Empty(1)
01: Sprint => Empty(1)
02: Rest => Empty(2)
+----------------------------------------------------------------
+ Built with SuckerPunch's Online Planner v5.0
+ http://planner.cohtitan.com/planner
+----------------------------------------------------------------
Archetype: Corruptor
Primary: Fire Blast
Secondary: Radiation Emission
+----------------------------------------------------------------
01: Fire Blast => Accuracy(1), Accuracy(3), Damage(5), Damage(17), Damage(40), EnduranceDiscount(46)
01: Radiant Aura => Heal(1), Heal(19), Heal(31), Recharge(43), Recharge(46), EnduranceDiscount(46)
02: Radiation Infection => EnduranceDiscount(2), Debuff_ToHit(3), Debuff_ToHit(7), Debuff_ToHit(17)
04: Accelerate Metabolism => Recharge(4), Recharge(5), Recovery(11), Recovery(13), Recharge(31)
06: Fire Ball => Accuracy(6), Accuracy(7), Damage(11), Damage(15), EnduranceDiscount(29), Damage(37)
08: Rain of Fire => Damage(8), Damage(9), Damage(9), EnduranceDiscount(15), Empty(45)
10: Recall Friend => EnduranceDiscount(10)
12: Enervating Field => EnduranceDiscount(12), EnduranceDiscount(13)
14: Swift => SpeedRunning(14)
16: Health => Heal(16)
18: Stimulant => Interrupt(18)
20: Stamina => Recovery(20), Recovery(21), Recovery(21)
22: Lingering Radiation => Accuracy(22), Accuracy(23), Recharge(23), Recharge(33)
24: Fire Breath => Accuracy(24), Accuracy(25), Damage(25), Damage(27), EnduranceDiscount(33), Damage(37)
26: Hasten => Recharge(26), Recharge(27), Recharge(31)
28: Choking Cloud => EnduranceDiscount(28), EnduranceDiscount(29), Basilisks_Gaze(34), Unbreakable_Constraint(36), Lockdown(37), Ghost_Widows_Embrace(43)
30: Mutation => EnduranceDiscount(30)
32: Inferno => Accuracy(32), Accuracy(33), Damage(34), Damage(34), Damage(40), Empty(43)
35: Fallout => Accuracy(35), Accuracy(36), Damage(36)
38: EM Pulse => Accuracy(38), Accuracy(39), Recharge(39), Recharge(39), Hold(40), Hold(40)
41: Power Sink => Recharge(41), Recharge(42), Recovery(42), Recovery(42)
44: Conserve Power => Recharge(44), Recharge(45), Recharge(45)
47: Charged Armor => EnduranceDiscount(47), Res_Damage(48), Res_Damage(48), Res_Damage(48)
49: Electric Shackles => Accuracy(49), Accuracy(50), Hold(50), Hold(50)
+----------------------------------------------------------------
+ Inherent Powers
+----------------------------------------------------------------
01: Brawl => Empty(1)
01: Sprint => Empty(1)
02: Rest => Empty(2)