too long for a case. Griffin's site has previews of some good cases for the Touch, but they're not available yet. Nothing but socks from Apple. Belkin appears to have a folio case and two versions of an armband case, but they're not too appealing for something like the Touch.
The screen is built to withstand scratches, but yes, it can get them like any other good piece of hardware. If scratches really bother you, then worry about the back. Like all original iPods, the back is the same as the Videos, or Classics, and the 1G and 3G Nanos. Easily scratched and not too great to look at, but oh well. My only complaint is why they didn't give it the same shell as the iPhone or something similar to the 2G Nano case. Very, very durable. But it is more of an iPod, and not an iPhone, according to Apple, so this was to be expected. I'm getting one, but it could be better.
Hope this helped.
-BMF