That is pretty interesting. What I wanted was a simple RS232 type that would turn a standard color PC monitor into screen display like the old LSI Blue Pig (am I showing my age?). I'm building updated electronics for 1950's era SUN distributor machine and a large 80 character display would be ideal. Target board is just a $3 mini. Add all this stuff on and you might as well go with a PC and get data storage. A month ago there was an article on a board here that turned your computer into an AV entertainment center. With remote it was only $15 shipped! I'm sure a simple board is out there though this has possibilities for graphs and control panels. Project keeps growing in scope. With all these snap on boards there is a concern about how many pins they use, you run out of empty pins quick.
Now if someone just made that into a board. 40 years ago I had a Z80 demo board and I interfaced it to a S-100 video board to make a word processor for a computer class. The days are over when I had to do that much work. Spoiled by all those under $10 boards from China.