[Coco] CoCo4?

[iggybeans at comcast.net]

It would be nice if Tony's Disto hardware was easy to recreate, but most information Tony released has been carefully re-worked with intention errors and ommissions. Not a new tactic to prevent replication, but after all these years a little silly. 
David Wien's Sardis Technologies no halt controller is documented well enough to replicate, but it would need a re-work replacing the multitude of 74LS chips with a CLPD to gain the extra space needed to add all the functionality you guys are talking about.