Still doing more stuff for other people than myself, but got another run at the MB6582. 3 parts to get, and it turns out that the ebay seller with the displays didn't ship what he thought. I have a 'plain, vanilla' black on green display, when I thought I was getting green on black 'negative'. I'll update once it's working. I had a reasonable idea for the display wiring, and put a single-in-line cable mount socket, (the kind you crimp pins to the wire, then insert into a housing), on the cable, and a 16 pin 90 degree pin header on the display. That means the fiddly display wiring only has to be done once, and I can change displays by simply plugging another one in. Pots for feedback were from Smallbear, and are neat, small Taiwan Alphas. I used heat shrink sleeving over the soldered pins to make the wiring more robust.
I Used some salvaged 2 pin computer pin connectors, from old PC cases for the 5V connections to the power LED, and teh fan, and a 3 pin one for the audio out. I have done connectors for all the I/O and the control surface connections, so that main board could be removed safely, if I need to work on it.
I hope to run it up next week, once my next batch of work is over.