1.) Glock 30. If you think you can conceal it well, nothing beats this. I like it better than the small 1911s and better than the XD.
2.) Taurus PT145. If the Glock is a little too big, go this route. You maintain 10+1 capabilities in a (mostly) smaller frame.
3.) Glock 36. After the first two, you're sacraficing 10+1 for 6+1. If those are too big, try this one next. It's thinner and shorter than the PT, but the same length of the G30.
4.) Kahr CW45/P45. These two models are ABOUT the same size, with the P45 being the pricier of the two. The length of the PT, but shorter, thinner, and lighter.
5.) Kahr PM45. This is quite easily the smallest of the bunch and, as such, only has a 5+1 capability.