if some aspiring ham woutld combine a FTDI chip, and the transistor switches on a small circuit board with appropriate cabling, that would be neat.
You just described a winkeyer. It even uses an FTDI interface. You can't bit bang one of those though.
the WINKEYER USB will provide the CW action, but it costs a lot more that the simple switch
No question about that.
also work for PTT and also FSK (which the WINKEY USB won't do).
It will absolutely do PTT, as well as work as a standalone keyer with memories. I'm not sure what you'd use CW FSK for (you mean MCW?).
If it's a desktop PC with a PCI bus, "real" serial cards are inexpensively available that would allow real bit banging.