Nobody on the Arduino team reads these? I cross-posted in the bugs forum:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1286350399
I put optiboot on a Duemilanove and it still works fine in this scenario, so it's not the bootloader.
It's a pretty serious usability regression compared to the Duemilanove. I hope they're focused on releasing the code for the 8u2 chip so that some progress can be made here in the community (although apparently the community of Linux Arduino Uno users is very small and non-vocal?)
I feel frustrated and with ever dimming hope of a solution.