Nick,
I'm so glad you revived this thread. I can't believe how it has taken off. With all of the activity, I hope the manufacturers will take notice and see that there is, indeed, a market for Penn Central equipment. Here are some of my suggestions:
GP-7/9
GP-30
GP-35
GP-38
U-33-B
U-28-C
U-33-C
40' PS-1 boxcar
PS-5 gondola
coil car
and...and...and...
Tom