Update: got my motor swapped out and am back in the metal cutting business.
The first of my version of the "universal" block is done. Dimensions as per the Kubota drawing at the start of this thread (except as noted), 6061-t6 aluminium, 30mm thick (original cover is 25mm, need the extra to accomodate the threads), ports tapped 3/8" NPT. Will come with four stainless 3/8" countersunk plugs rated 3,000psi for unused ports and 2 new o-rings.
While the ports on the face are 35mm apart as shown, the ports on the long side are 32mm separation. This is to ensure sufficient material between the ports and the mounting bolt holes.
The other four blocks are milled, just have to drill and tap them now.
Material cost including plugs and o-rings works out to about CDN$20. Plus something to heat the shop and run the machines. Call it CDN$30 (or US$25) + actual shipping by Canada Post from P1H 2J4. (Note: I don't know how much Dan wants for his, but shipping in the US would undoubtedly be cheaper -- Shipping in Canada is nuts.)
One per person for now, just to make sure there's enough to go around.