I can tell you from personal experience (hardship!) that cutting stations from MDF is very time consuming as the jig-saw blade doesn't travel through the material very quickly. Granted I used 3/4" MDF, so my stations will likely be discovered by paleontologists years from now, but I think straw-board (which seems to be very common at Home depot and the like) would be a good alternative. Many builders seem to use plywood, but I found it a challenge to find unwarped examples. Though, if you can find a nice flat 5/8" thick 4'x8' board, I think that's your best bet.

Rob