Well, the current VMBuilder available on the git archive now supports building Lenny on vanilla Xen. We're very close to building AMIs, I can almost taste it. (The reason why you haven't heard about this until today is that accessing Blogger is super-finnicky when not logged in for absolutely no reason at all. My apologies for the lack of updates on this blog.) Additionally we're starting to actually put documentation and stuff on the wiki [1,2,3] about the GSoC project and euca2ools.
The next step is to look at a few packages called 'ec2-init' and 'ec2-modules'. They only exist in Ubuntu right now, and I purposefully disabled VMBuilder from installing them on Debian so far since Debian doesn't have them. That, and I believe I should pick out a suitable AKI/ARI combo sometime (the AKI info in the Debian plugin is just a placeholder right now). This shouldn't take too long. I would like to get the VMBuilder changes in Debian soon, and hopefully get those changes in the VMBuilder trunk too.
My project was part of the Debconf talk on the Debian GSOC projects which I believe was 2 or 3 days ago. I'd look up the presentation and watch it but right now I have my friend begging me to install Ubuntu for him so he doesn't have to use Vista anymore.
(that's a lotta gits)