I imagine the PTHs will be updated with the tracks on the official configurations, but we could really do with a PTH-making tool of some description for custom tracks. (IIRC I had a tinker a while back, but can't remember what issue I ran into to stop me... will look again sometime
)
Thinking aloud: I know (think!) they're needed for TV-Director and live-lap type things, but is it also the PTH file the AIs use to drive? Would we be able to get them on custom tracks if we could build our own PTH files?