Sorry, I shouldn't post while sleepy, you are absolutely right about thumb. (Once upon a time, I had educated myself pretty thoroughly on this...)

And yeah, now that I've got an Android device, I guess can use it as my phone and set up both my N900s as test devices -- one for cssu/thumb, one for stock.

I guess it's also time to start trudging back through all that Sandbox stuff, and somehow scrounge up a machine (real or virtual) to run Debian or Ubuntu. Bleah. (Any chance I could just integrate the thumb toolchain into the Qt SDK? )