He does. He's been a great help as I try to piece together enough stuff to function as a system element. And thank you for that redbook link; I have a load of stuff, but somehow missed that one. Thanks!
The MP3000 (Multiprise 3000) is the smallest mainframe IBM ever made, weighing in at only about 300 lbs. Using the vanilla Hercules, it can be MIPS limited to act mostly like a MP3000 System/390 machine and run the same OSes.
Also check out the OS/390 ADCD Redbook:
https://www.redbooks.ibm.com/redbooks/pdfs/sg246204.pdf
Which I found pretty helpful for finding my way around. (I see from the cover that it includes MP3000 info!)
Edit: Have you seen this? (I think this guy hangs out on HN)
ftp://ps-2.kev009.com/incoming/timc/PDFS/IBM/S370%20&%20S390/MultiPrise%203000