Amazed and happy to see so much homebrew work still going on. The Veronica project on this site is fascinating.
Let me self-promote my bitbox arm32 home-brewed console since it's somewhat on topic although less retro minded (https://github.com/makapuf/bitbox/wiki)
edit : added link
That's a nice project. Ever think about adding an HDMI output? :)
Fast-forward to the finished (and resurrected) project so you can see the backplane: http://quinndunki.com/blondihacks/?p=2644