I have exactly the same problem - the developer download froze my iLiad on a screen saying "-- Download Complete --" and now it's in an infinite reboot loop and I can't turn it off to reflash!
The annoying thing is, I recharged it yesterday afternoon so it's going to take ages for the battery to run down. I've taken the stylus out in case that helps, but otherwise I'm left staring at a rebooting iLiad for the next
n hours
I have my CF card and the reflashing files at the ready - keeping my fingers crossed...