I am going to play with this alot more before it's done.
I agree that inside bearings would be better. I will need to get the studs offset by 1/2 pretty quickly since I am looking at a 3 wide inside base.
I am going to further sacrifice the old plastic truck axle sets to see what I can get. The thicker portion around the metal axle is molded 1/2 and 1/2 to the back of the wheels. If I can get the wheels off, I can cut that axle covering section off.
I would still rather use metal wheels. I am a 3 rail guy so a short from one wheel to the other doesn't bother me, and the rolling resistance of metal on metal is much lower than plastic on metal.
O well, several iterations to go, we will see what happens.