OK, OK... I promised I wouldn't rub it in about the ArduPilots, esp since people called me greedy!
But Ren, you seem to be buying the knock-off EZs a case at a time and the ArduPiolots 63 at a time... looks like you're going to have quite the fleet going!
Thanks for the bulk-airframe pointer. Even if they're a bit delicate it might still be worthwhile at <$20 per airframe. I'll definitely try to keep blogging as I (fail to) make progress. Gumstix kit turned up today, so that's this weekend spoken for...