Amiga MIDI over USB (via Deneb)?

[Tension]

What software is there out there that will take advantage of a MIDI USB interface? I know OctaMED won't so what is there?

Well, in theory OctaMED should work with CAMD.device.

[Tension]

Eh? IIRC the Amiga already has a midi interface built-in. It's on some of the pins of the serial ports which were defined in RS232 to be reserved/not connected.
Amiga Serial port pinout
(audio in/out are the ones needed).
It shouldn't be too hard to solder a MIDI connector yourself (or let someone do it for you).

Sorry but ur wrong

[Tension]

humhum, yes, but still, building an Amiga-MIDI port is very easy considering this scheme

True, but you can buy them second hand for pittance anyway.