Check BidOrBuy, there's a whole slew of inexpensive LCD kits being sold on there for use in cars for (fairly) little.
Their resolution and PPI (pixels per inch) ratings won't be the best in the world, but then, you're going to pay a premium for any high-quality, high resolution small form factor screen.
Most are made to run on a composite connection, though most graphics cards have a video out in s-video form these days, even some netbooks, and you can simply use a s-video to composite converter for that.
They'll still need to be externally powered, though. Being low voltage/current, you could probably get away with powering them via USB, though you'll want to make very sure of their draw ratings before jury-rigging a USB cable onto the power cable lest you want to burn out a USB controller on your board.
*edit* Also, it'd help if you could explain what you want to use these for. If you're looking at DIY projectors, I can tell you now you're better off just going with the bigger, bulkier versions for a first-time construction. It'll save you a lot of money, time, frustration and is easier to 'sort out' if your initial build doesn't come out perfect. A 17" 1280x1024 monitor will work fine for one of those, just make sure that you can retain aspect ratio with the panel and that it ideally doesn't have an anti-glare coating on it.
If you're looking at the LumenLabs forums' articles, try and find a panel that's been checked out by one of their members to ensure you don't encounter FFC issues.
http://en.wikipedia.org/wiki/Flat_Flex_Cable
Y'know, just in case that's what you're up to.