Apparently there are a fair number of persons willing to invest time & energy into resurrecting IBM's old MVT operating system. Personally, I blame Rick Fochtman, who created an OS/360 archive cd/rom containing MVT, and his co-conspiritor Roger Bowler, who is creating Hercules, a 360/370/390 emulator running under Linux. Here's the latest info I have on joining in on the fun at the Hercules-390 mailing list:
There are also some sites which offer downloadable versions of Rick's cd/rom, mentioned in the Hercules FAQ.
New User Documentation
MVS 3.8J distribution is now available to download
Hercules S/370 & S/390 Webring