I spent a good part of my day on my new buildbot setup. I finally configured to build a nightly images for all of the supported architectures. I also changed the worker to a local worker for simplification.
I have setup my own instance setup on my faithful Dell Dimension 4600 to build gentoo images this evening. The next step will be to configure a buildbot builder that will test my images using qemu.
Here are the steps: 1) Bootstrap stage3 from remote mirror. 2) Generate gentoo chroot. 3) Build generic stub kernel for recovery (genkernel all). 4) Exit chroot. 5) Create raw disk image. 6) Partition disk. 7) Mount as loopback. 8) Copy files from chroot to disk image. 9) Boot qemu vm from image. 10) Detect hardware and automatically configure proper kernel.