Yeah, probably nobody other than me will ever use it, but I enjoy hardware hacking, even if it's on obsolete hardware.
Also, my whole motivation for this is to be able to "slave" my RCX to my EV3 to make it easier to use my old 9V motors and sensors. (at least for stationary models - its hard to imagine an EV3/RCX/Tower bohemouth rolling around
Sometimes the micro motors, 9V gear motors, and smaller sensors fit nicely into places that the EV3/NXT stuff won't fit.
BTW, your LLC code (in the firmware and Java code) is functioning very well. I've been "tuning things up" in the original PC side tower code (making more agressive use of non-blocking IO), and am able to get about 20ms single byte round trip times to the RCX with ~100% reliability. That's really quite amazing for a 2400bps half duplex IR connection, and says a lot for the design of the original hardware / firmware.