Wolvix|Cub is a smaller version of Wolvix which should fit on a 256MB USB stick.
Wolvix Cub comes with both Fluxbox and XFCE and includes a carefully selected group of development, graphics, multimedia and desktop applications. I'm actually surprised how much software I managed to include on 243MB.
New in the Wolvix 1.0.5 series is the Wolvix Control Panel (WCP) which is a suite of admin utillites. It's in early development, but still features a handfull of applications like the 'Wolvix Installer' which enables you to install Wolvix to your hard drive. (Both 'Normal' and 'Frugal' install.) And install Wolvix to a USB Flash Drive. WCP also has tools for X-window configuration and lets you start/stop and configure CUPS easily.