Hi Gilrock,
Sounds like you are well on your way to building out your own fully dynamic art cab, and the experience you have from building a multi-pin will make this build easy for sure. I tore apart this cab because I was never very happy with the screen angle and size, so it just made sense to go back and 'get it right'.
This build is fully operational now and has been put through it's paces at one of my arcade parties already with 4 people mashing away on it so I'm very happy with the way it has turned out. I've been spending time configuring the front end and setting up my Daphne emulator properly lately, now it plays 15 LD games woooo hooooo!!!!
4 player configuration works perfectly, as does Hyperspin with the dynamic marquees, also the servo controlled joysticks kick ass, switching between 4 and 8 way as you pick games or go back to the Hyperspin menus. Oh and yes I finally got rid of my nag screens

I still have work to do around the top of the cabinet, building out the housing for the marquee and generally making it all look more integrated, but my time is stretched across my whole collection these days so there haven't really been any interesting updates to post for a while.