Slide over to the thread titled :
Folly has been working the hell out of the Libretro MESS/MAME core addition to Retropie and just recently dteam and I have been helping him test and tweak the Tandy Coco 1/2/3 setup to be a one-click game play. Setting up the controls hasn't been covered just yet, but we're getting there.
Read the last few posts and see if it interests you. Our goal has been to get MESS involved more as a goto for all the other computer and hand-held games. So they can be used in Retropie...again... one click to it goes right to the program and auto-loads without any user input (or as little as possible)
This is the Tandy Coco3 running in lr-mess with a backgorund I reworked from another artist adding in the proper Tandy screen and other stuff. You can see it's working good. Just haven't gotten the retropad control to work just yet as I haven't been focused on that aspect.