I have been looking into a workaround for this bug and finally found a way.
There is a supposedly leaked (from Google) Android Developer Phone firmware version 1.1 image floating around on the Internet. The first one to post it seems to be:
http://andblogs.net/2009/01/new-adp1-images-leaked/
I downloaded this image and with the help of the procedure described here:
http://antonmelser.org/open-source/backup-install-restore-adp1.html
I managed to upgrade the firmware on my Developer Phone. The link above assumes you run Debian Linux, but if you have the Android SDK setup on Windows, the only thing missing is the "fastboot" tool. I downloaded a pre-compiled binary of "fastboot" for Windows from here:
http://forum.xda-developers.com/showthread.php?t=463627
The first time you start your phone with the new image, it takes a while to start, but should then manage to unlock the SIM card make calls. The "About Phone" settings now shows "Firmware version: 1.1".
One final note of caution: There is no way to confirm that the binary files discussed above do not contain malicious software. The conservative approach would be to wait until Google officially releases the 1.1 firmware. That said, I have not experienced any problems (but I only finished about 10 minutes ago).