FLEX-ES (formerly OPEN/370) provides a System/390 on a Pentium.
It includes system-mode operation, runs 8 popular S/370 OS's.
On a 2-processor Pentium-II/400MHz,
it provides 7 to 8 MIPS on one processor and I/O functions on the other
They also sell installed systems (hardware/software turnkey systems).
FLEX-ES home page.
From instruction-set simulation and tracing