Under the unique maps option is the freakshow warehouse from the "Freakalympic" arc, complete with multi tiered room and podium.
Art of War Co-Leader - Union *Global@Warscythe*
"The box said Windows Vista or better - so I installed Linux"
Excellent, I'll go find it. 
It has no back marker for spawns. 
The boss spawns in the middle of the map.
The Freakshow office is in too.
I really should do something about this signature.
I take you to this thread!
HERE WOOOOO IM A LINK!
Cant seem to find my original thread with all the maps on so that list is just the nonunlockables, trying to find the thread with them all on [but seems that a few of the early pages got deleted? meh will have to dig through comp to find them] Anyway think the map your after is the warehouse > freakshow [1]
@Damz Find me on the global channel Union Chat. One of the best "chat channels" ingame!
Are there any Freakshow maps in MA?
Preferably the office one from mission 'Recover Stolen Weapons from Freak Show' (20-25 arc).
Either that or a warehouse type. I had a look but couldn't see any which surprised me as I thought I had seen one in the past.