Comment 9 for bug 468809

Actually, "--ppa" sounds as complicated as "--mirror" to me. You have to do (too) much effort to build an ppa first. The workaround proposed by Nick sounds better in this respect, but still I think that it has the disadvantage that it is tinkering, because you copy in deb files which - even when you remove them after installation - result in an unclean, not size-optimized image.

Summarizing, we have two workarounds:
a) using --mirror or --ppa: Leaves image clean, but requires additional setup effort
b) using a self-scripted solution: Leaves image unclean, but requires only few additional setup effort

What I was thinking about is a solution, that leaves the image clean and requires NO additional setup effort except using the "--add-dpkg" switch. This would be a very basic but clean solution. Of course, internally it could be combined, i.e. vmbuilder could setup its own ppa, copy the specified deb files there and do rest like if the user provided the "--ppa" switch him/herself.