Does anybody know where to find something in NJT? Cars, locos, anything.
You'll need to do some repainting, but Bachmann's E60CP could serve as one of NJ Transit's ex-Amtrak E60CH's. Unfortunately, it's only included as part of a train set, the Cenntenial.
http://www.hobokenterminal.com/alltime/photos/e60/njt_958_e60cp_south-amboy_10-83_landau.jpg
http://www.hobokenterminal.com/alltime/photos/e60/njt_961_e60cp.jpg
Imperial Hobby Productions makes a resin shell of a GP40FH-2. unfortunately, it's only avaiable undecorated and unpowered.
http://ihphobby.tripod.com/
Life-Like used to make an F40PH-2 in New Jersey Transit, which would undoubtably be the easiest option of the three. Unfortunately, I think it's been discontinued.
Those are the only three that I know of off the top of my head. Microscale does make some NJ Transit decals, however.
You will often have difficulty finding any ready-to-run models of locomotives and cars for commuter authorities. Since commuter service is very much a money-losing operation, the authorities view licensing fees as a source of revenue to reduce their deficits. The fees are high enough to discourage sales of such items to modelers, so most manufacturers simply do not make models.