As far as I know, there are some emulators of Mac for PC (Mac on USB, maybe? and Atari ST that could do the trick. IRIX port could be ported (again) to Linux, and Palm OS are still alive, so you could play Mazewar anywhere.

I guess there are no emulators of IBM 1800 nor IMLAC, but...

I was installing Debian on my "new" laptop (a second-hand Fujitsu C 6387) and I saw there are a package called simh that have 33 emulators of computers...

This is the SIMH set of emulators for 33 different computers: DEC PDP-1, PDP-4, PDP-7, PDP-8, PDP-9, DEC PDP-10, PDP-11, PDP-15, Data General Nova, GRI-909 Honeywell 316, 516, HP 2100, IBM System 3 Model 10, 1130, 1401 IBM 1620 Model 1, IBM 1620 Model 2 Interdata 3, 4, 5, 70, 80, 7/16, 8/16, 8/16E Interdata 7/32, 8/32 SDS 940 LGP-21, LGP-30 DEC VAX and VAX 780 (but cannot include the microcode due to copyright)

May it be useful for playing? Their web page is http://simh.trailing-edge.com/