Spork? I know many of the Bemani arcade collectors, but not them all, of course.
And yeah, the DTX (actually, any old MIDI device on channel 10) will work with 3rd/2nd, but none of the other old ones. 3rd/2nd was of course the last one before V was released, so it was nice at least that it supported the MIDI option. I'm churning out a somewhat finalized build of the MIDI to Digital PS controller adapter if you're interested. Waiting on the microcontrollers to show up.
Also, if you happen to have a IIDX machine and want to play the CS versions on it or use it with a PC, have I got the board for you... Working on a similar adapter for DDR (DDR is electrically very, very nasty), but it'll be a while. I had a request for a para para USB adapter, too, but I haven't done anything with that since the person who was interested doesn't actually have the machine at his place yet.
Most of my Bemani hardware tinkering has been related to hooking up CS and emulation to the real cabinets since the real upgrades are so darned expensive to put in a basement arcade, and of course using a home version is completely legit if it's actually in a home.
HUM: I may be off by a version here - I don't play the CS GF/DM much as I don't have a worthy controller. The only "older" (pre-V) version to support the USB MIDI option is the Guitadora bundle, whatever arcade releases that was meant to mirror.