Honestly, I would go with a KJW 1911. I've been playing with a gas model and it's a great little gun; it's my favorite CQB piece. It'll run ya about $110 from Evike (without the 20% coupon code) for one with a CO2 mag. Great kick, pretty darn accurate (for CQB), and compatable with a ton of upgrade parts. Best thing is, if you ever decide to run green gas/propane, you buy a gas mag and neve have to worry about converting anything. It'll run either gas or CO2, depending on the magazine. Best part for you is that it uses a ton of gas for recoil, so the fps is low considering gas consumption.
http://www.evike.com/product_info.php?cPath=21_45_241&products_id=28652
I've had the KJW KP07 GBB 1911 for over 2 years now. Been nothing but reliable both as a primary and secondary weapon. That said, its ONE flaw would be those Co2 mags. When I bought mine it came with one Co2 and one green gas mag. Pretty much right out of the box the Co2 mag would leak gas on occasion, and eventually the whole follower broke, rendering the magazine useless. Gun itself runs great on both mags, and I haven't had any such issues with any of my green gas mags. Would highly recommend the gun to anyone, but not necessarily purely for Co2 use (though that's about as good as you're gonna get as far as quality without going green gas instead).
Also worth mentioning; the Co2 mags brought the FPS up to the ~350 range, up from the ~330 it shoots on green gas, so it may not be field legal in all CQB situations if you decide to run it on Co2. Gas consumption was great though. I max out at 1.5 mags on a full green gas fill. With a full Co2 cartridge I could hit just over 3 full mags before running empty.
