Even if it does have dedicated graphics, anything that could be considered ultraportable doesn't usually have very good dedicated graphics. For example, you can get the Latitude D610 with discrete graphics (it's pretty small, not exactly ultraportable), but it's only got the X300 I think, which doesn't exactly blow away the Sonoma GMA 900. You should be fine doing some light gaming with any Sonoma system if you're not too hardcore.
The Dell X1 would be a good choice if you want something that small. I've been looking at that, but I've decided I'd much rather have a 14" widescreen with a full-sized keyboard.
With any laptop you want to be able to try it out first, but that's even more true with the ultraportables. Make sure you're comfortable with the keyboard/screen size.
I'd get the Asus W3V in your situation if I was really that concerned about gaming. It's a 14" widescreen, though, not a 13.3". It's pretty borderline ... it's 5.5 lbs... not exactly ultra-portable.