Stew, well spotted! Fantastic, that works - I loaded it up with my small collection of games cartridges, and the pokes happily switched between them. So neat! Who needs a Tandy MPI eh?
So here's the 'Mega-Dragon', fully loaded with a Coco-SDC, the Speech&Sound cart, Tormod's new 512K expansion card and the classic Chess cartridge. What more can I want? Well, actually, I know - I have a real DOS cart too, but no floppy drive. I'll have to tweak Pere's DosPlus to support the Race, as his code works with an MPI, but that doesn't look tricky. Then I'll have one seriously blinged out Dragon!