The MCI JH-110 is a nice deck, which is capable of being configured into 1/2" 4 track. More often than not, you'll find them configured for 1/2" 2 track, or 1/4" 2-track, though, because they're primarily used for stereo mixdowns.
Film studios, and post-production studios are where the 1/2" 4 track format was most used, as they needed that fourth track for a SMPTE time code track for film sound.
Firestation recording studios has one, but 2 of the 4 track electronics modules are shot. However, I THINK we still have the 4-track headstack laying around somewhere. They MAY want to sell it if you're interested. However, you'd have to either find a machine with 4 track modules already in it, or find your modules elsewhere.
It's one beast of a machine, but when well kept, it'll never let you down. If you can find one in good shape, and you're willing to invest into the tools needed to keep it pampered and running smoothly, go for it.
good luck!
-callie-