Just "discovered" although hiding in plain sight, I moved it out of the way a half dozen times in the great M571 hunt, is a Shuttle AV11 Apollo Pro socket 370 board. For some reason it's existence was slipping off my brain like water off a duck's back. Now it became relevant because I have a bunch of socket adapters and 3 more s370 CPUs roll in, though I had 5 CPU I could have considered it for previously, so I don't know why I was just flat out ignoring it. Looks like it needs caps though, as does my other Apollo board a DFI CA64, which by all accounts is a bit of a slow turd. Not much info around about the AV11 though, so don't know if that's going to be just as bad since it was utterly forgettable it seems. Usefully it appears to support mendocino and coppermines, so if it's running sweet after a recap, I can verify operation of a small pile of CPUs.... then it gets either the powerleap or lin-lin Tualatin adapter on it for some Tualeron action.
Also strangely blindspotted, was an Asus P5A-B which I hope will run a K6-2 nice.
M571 and the Voodoos still seem to be vacationing on the island of lost toys.... they also might have a SiS Xabre with them, since I recall having one of those, but it's not "around" at present.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.