The other day I learned lr-mame2000 doesn't save high scores. Part of me thinks I should just accept it. But the more I play the more I want to have the high scores saved over time. Being on or first on the high score table is part of the arcade experience. (Ideally I'd love it if Libretro saved the entire system state on exit so it wouldn't have to go through the initialization sequence.) And while lr-mame2003 does support high scores, it needs more CPU. So either I'd end up cutting my list of playable games even more or I need to get another RPi - and I'd rather not spend even more $$ on this project.
OTOH, prior to making my barcade I was using the Raspberry Pi Zero to play back DVD rips (no problem with the MPEG-2 decoder licensed/enabled); so in the long term I'd want to buy a second RPi anyway. (Heck, I suspect eventually I'll get a third to hook up as a retro console.)
So two good reasons won over my frugal nature and I bought a Raspberry Pi 3 A+, which fits my requirements perfectly. I've ordered
Of course now I will need to go back through the list of games and see if there's any other "best of the best" which are now playable.
For the actual build the current bottleneck is creating artwork for the control panel. Much to my relief others have confirmed vinyl is durable enough for the control panel and it's not necessary to cover it with plexiglass or lexan. This great because I suspected it would take me several tries to successfully bend & cut holes in the plastic (plus I'd need to buy a bit for my router). My plan was to use macro photos of quarters as a background. However, it's amazing how scratched a quarter can be even if it looks "mint" under a magnifying glass.