There are a lot of "as delivered schemes" that have not been touched yet. It seems like all the schemes are post 60's so far. Early B&O, WM, C&O would be much appreciated. The only one I have bought so far was the Pennsy, because it was an early scheme.
Speaking of that, for being a B&O modeler, I sure have been spending a lot of money on PRR locos. I think the last 5 I have bought were PRR (Atlas S2, Bachmann K-4 x2, BLI M1 x2).