Have you looked at Ann Taylor or Ann Taylor Loft? I used to work there, and I know they carry the same suits they have in regular in petite's sizes. They're good basic suits, usually with some up-to-date detailing, and reasonably well-cut.
I'm short, too, and I really love JCrew suits. I always feel like they are cut really well and skim my body nicely, giving a nice tailored look unlike others that make me look even shorter!
They have lots to choose from, but their lightweight wool suits can be worn any time of year.
Express and Limited have suit jackets that are cut very feminine and the pants come in a range of sizes.
The suit jackets I have are lined with polyester. If you end up liking the suit, i would probably have it relined. They won't last forever because they aren't wool, but they look really nice and they are light, so it might be worth it if you aren't going to wear it often.