*Takes a sip*
Ptah! Disintegration!
Build looks good. With accolades, you could swap the pshifter E/R for a generic endmod and be just 2hp below the hit point cap for a bit better recovery.
As an aside, the defiance boost from Ice Patch is like a mini build-up. Drop this after your controls, just before you switch to blasting. 
Though Beam with Ice sounds like something I might order at a bar, in this context it's a pairing of powersets I've never played before. The word on the street about Beam Rifle seems to be that to make best use of it you have to really focus on using its powers. Ice Manip looks like it allows that - drop an Ice Patch, throw out a Shiver, BU and start blasting.
I whipped up a s/l soft-capped build with decent recharge. Actually I made 2, the one I pasted below is with Cold Mastery, I also made a Mace Mastery build but lost it. No great loss because I think I like the variety of powers in Cold better, even at the expense of Energy defense.
So... whatya think?
Hero Plan by Mids' Hero Designer 1.952
http://www.cohplanner.com/
Click this DataLink to open the build!
Beam-Ice-Cold: Level 50 Science Blaster
Primary Power Set: Beam Rifle
Secondary Power Set: Ice Manipulation
Power Pool: Speed
Power Pool: Leaping
Power Pool: Fighting
Power Pool: Leadership
Ancillary Pool: Cold Mastery
Hero Profile:
Level 1: Charged Shot -- Decim-Acc/Dmg(A), Decim-Dmg/EndRdx(5), Decim-Acc/EndRdx/Rchg(5), Decim-Acc/Dmg/Rchg(23), Decim-Build%(23)
Level 1: Chilblain -- Enf'dOp-Acc/Rchg(A), Enf'dOp-EndRdx/Immob(37), Enf'dOp-Acc/Immob/Rchg(37), Enf'dOp-Acc/Immob(40)
Level 2: Cutting Beam -- Posi-Acc/Dmg(A), Posi-Dam%(3), Posi-Dmg/Rchg(3), Posi-Dmg/Rng(19), Posi-Acc/Dmg/EndRdx(19), Achilles-ResDeb%(39)
Level 4: Ice Sword -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/EndRdx(21), KntkC'bat-Dmg/Rchg(21), KntkC'bat-Dmg/EndRdx/Rchg(25)
Level 6: Disintegrate -- Decim-Acc/Dmg(A), Decim-Dmg/EndRdx(7), Decim-Dmg/Rchg(7), Decim-Acc/EndRdx/Rchg(11), Decim-Acc/Dmg/Rchg(11)
Level 8: Aim -- Rec'dRet-Pcptn(A), Rec'dRet-ToHit/Rchg(9), GSFC-ToHit/Rchg(9), GSFC-ToHit/Rchg/EndRdx(43), GSFC-Build%(43)
Level 10: Chilling Embrace -- EndRdx-I(A)
Level 12: Lancer Shot -- Dev'n-Acc/Dmg(A), Dev'n-Acc/Dmg/Rchg(13), Dev'n-Acc/Dmg/EndRdx/Rchg(13), Dev'n-Dmg/EndRdx(15)
Level 14: Hasten -- RechRdx-I(A), RechRdx-I(15)
Level 16: Build Up -- Rec'dRet-ToHit(A), Rec'dRet-ToHit/Rchg(17), GSFC-ToHit/Rchg(17), GSFC-Rchg/EndRdx(39), GSFC-ToHit/Rchg/EndRdx(43)
Level 18: Super Speed -- Winter-ResSlow(A)
Level 20: Ice Patch -- RechRdx-I(A)
Level 22: Combat Jumping -- LkGmblr-Rchg+(A), Ksmt-ToHit+(40)
Level 24: Boxing -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/EndRdx(25), KntkC'bat-Dmg/Rchg(27), KntkC'bat-Knock%(27)
Level 26: Piercing Beam -- Posi-Acc/Dmg(A), Posi-Dmg/EndRdx(31), Posi-Dmg/Rchg(33), Posi-Acc/Dmg/EndRdx(33), Posi-Dam%(33)
Level 28: Shiver -- CtlSpd-Acc/Slow(A), CtlSpd-Acc/EndRdx(29), CtlSpd-EndRdx/Rchg/Slow(29), CtlSpd-Rng/Slow(31)
Level 30: Tough -- S'fstPrt-ResDam/Def+(A), S'fstPrt-ResKB(31)
Level 32: Overcharge -- Posi-Acc/Dmg(A), Posi-Dmg/EndRdx(34), Posi-Dmg/Rchg(34), Posi-Dam%(34), Posi-Acc/Dmg/EndRdx(36)
Level 35: Flash Freeze -- FtnHyp-Acc/Sleep/Rchg(A), FtnHyp-Acc/Rchg(36), FtnHyp-Sleep/EndRdx(36), FtnHyp-Plct%(37), FtnHyp-Sleep/Rchg(39)
Level 38: Snow Storm -- EndRdx-I(A), ImpSwft-Dam%(40)
Level 41: Weave -- LkGmblr-Def/EndRdx(A), LkGmblr-Def/Rchg(42), LkGmblr-Def/EndRdx/Rchg(42), LkGmblr-Rchg+(42)
Level 44: Freezing Touch -- BasGaze-Acc/Hold(A), BasGaze-Acc/Rchg(45), BasGaze-Rchg/Hold(45), BasGaze-EndRdx/Rchg/Hold(45), HO:Nucle(50), HO:Perox(50)
Level 47: Frozen Armor -- LkGmblr-Def/EndRdx(A), LkGmblr-Def/Rchg(48), LkGmblr-Def/EndRdx/Rchg(48), LkGmblr-Rchg+(48)
Level 49: Maneuvers -- LkGmblr-Rchg+(A), LkGmblr-Def/EndRdx(50)
------------
Level 2: Swift -- Run-I(A)
Level 2: Health -- Numna-Regen/Rcvry+(A), Mrcl-Rcvry+(46)
Level 2: Hurdle -- Jump-I(A)
Level 2: Stamina -- P'Shift-EndMod(A), P'Shift-End%(46), P'Shift-EndMod/Rchg(46)
Level 1: Brawl -- Empty(A)
Level 1: Defiance
Level 1: Sprint -- ULeap-Stlth(A)
Level 2: Rest -- Empty(A)
Level 4: Ninja Run
Global = Hedgefund (or some derivation thereof)