I welcome Tangent to the O scale market. With that said, I suggest producing a freight car from the 1970s - 2000s era in plastic. The tank car is beautiful but it is for those who model the steam era.
Most of us, I'll say 75% want something that we see on todays current railroads. I believe the sales would be much more impressive and the 6 figures it takes to make plastic molds/tooling will pay for itself in the long run.
I model Illinois Central in the "dark star" paint scheme. I'm chomping at the bit to get my hands on those new cabooses on the Tangent web site.