The QS20 looks interesting, sad to hear it didn't work for you. Do you have any good links for developing for it? The little bit of Googling I did for QS20/21s just found glossy type info and few concrete examples of things that you can do with it.
The QS20 uses the same Cell SDK as the PS3. It probably also runs the same Yellow Dog distro. It's kind of pointless though since it's so expensive and difficult to program.
I got seven QS20s for $700, so I was happy. Older Cell blades are more affordable than you might think.