If you want compact and thin, try looking at the Khar k9, p9, etc. I'm a big fan, but they're a little heavy.
Heard good things about the new Keltec, but I was never a fan of their triggers.
Sig P239 is another option as is the S&W 3919 or the economy model 908 (if they're still making it).
If you're a fan of the single action, look at Springfield. They recently came out with a 1911 that is completely scaled down for 9mm proportions (not just rechambered). Should be nice and thin, but I haven't handled one.
LG