I recently got a High Noon Bare Asset to fulfill my IWB needs for my S&W 638. http://www.highnoonholsters.com/Prod...are_asset.html They cost under 30 bucks, and can get to you in under a week. I've also seen a lot of people on here using the Mister Softy, which is the same without a cant.
I haven't seen any problems with this holster yet. It gets used when for some reason I don't want to strap on the 1911. Retention is good with it, the holster is pretty versatile, and easy to put on/take off. It's thin and does a pretty good job of concealing if you find a good spot for it along your belt. The material it is out of seems to be able to take a beating too. My only other attempt at IWB with this pistol was an ambi Uncle Mike's nylon rig, I bought when I was new to carrying, needless to say that one didn't really work. But I got this one for around the samee price as the Uncle Mike's and it is vastly superior.
As far as no cover garment, I assume you mean no dedicated one (like a vest of jacket), I used this holster with just jeans and a t-shirt, and it did just fine.