Just found your question after a google search and registered here:
I was fed up with the restrictions of MIDI already in the 90tees were I intensively made musics. As most of you know, MIDI comes with certain speed limitations since the 31kBaud bandwidth a poor and not appropriate to transport detailed knob or key behaviour without latency. A 3Byte MIDI message already contains too much latency in order to do what I wanted (echo via midi) so I started to think about enhancements.
Honestly I expected MIDI to develop similar to USB progressing in speed, what never happend. For my own system I invented MIDI over S/PDIF to synchronize my audio boards since the 4MBit of S/PDIF transceivers leads to less latency.
I always used coax for it and never thought about using CAT cable. Coax is of better quality.
Well CAT5 is cheap and Ethernet Bandwidth is much higher today. One can transport 1GiG with a CAT6 oder CAT5-E but this requires echo cancelling and pulse amplitude modulation (5PAM) by the PHY, which has to be implemented into the gear first in order to use it. S/PDIF is already there http://www.96khz.org/htm/midiviaspdif.htm
My suggestion to MIDI.org and some vendors like Tascam, Alesis to define a 3Byte MIDI into the S/PDIF protocol layer never was taken serious, although it would have been very easy for the musical instruments manufactures to route incoming S/PDIF data through their DSPs and get high speed MIDI this way with existing gear. Also S/PDIF was established well for computer sound cards already. (My Soundblaster AWE did that 1993).
Using a reprogramed SoundScape Mixtreme Soundcard with a DSP, I accessed my gear with exactly this method. The next step was to use a 8 channel protocol like Tascam's TDIF or ADAT.
Well in the meanwhile they try to establish MIDI over ethernet, which to me is a dead horse, since USB3.0 is much quicker, and transceiver chips are cheaper too. Also, wiring a computer into the music tool chain does not require an additional network card (NIC) or possibly a switch, but has USB channels already integrated. Currently it is already an advantage to use USB 2.0 sind it comes with 480MBit. In 5 years, every computer will have USB3.0 which will be both MIDI interface and audio interface. This is, what I am focussing too!