Tom,
You may want to check into Photo Warehouse. They cut film to the size that you need. Their film is 125 and 400 speed and people who have used it seem to indicate that it is FP4 and HP5+ purchased by them in large sizes and cut down and resold under their private label.

Regarding TriX in ABC pyro, it is an unforgiving film in my experience. The highlights will block up very easily when the shoulder of the curve is breached. I have shot TriX for years in 4X5 and developed in HC110. However since I now use pyro exclusively, I don't find the film nearly as good as my other favorite Bergger BPF 200. However that film is not capable of a great deal of expansion. Others have indicated that HP5+ suffers from the same problem but that FP4 is a film that will handle expansion very well.

I have heard some very glowing reports on Efke films as well. This film is European in origin and sold by J&C Photo in Shawnee Mission, Kansas. There are posts reporting other's experience with this film on MichaelandPaula.com.

I anticipate switching to Pyrocat HD and FP4 and HP5+ or their equivalent at Photowarehouse for my 12X20 negatives. This is based upon the testing information that others have shared with me. There is a good source of test information on these films and that developer on Unblinkingeye.com. I personally see no need, for myself, to reinvent the wheel in the testing arena, since a lot of documentation exists on this film and developer combination. Hope that this helps, good luck.