Korg Mono/Poly

Hi,

I am thinking about donating a MIDI interface to my MonoPoly. Not only a 
MIDI/CV interface, but a real MIDI, because I want to control the 
arpeggiator chords from MIDI.

There seem to be two possibilities:
http://www.analogsynthservice.com/poly6.html from Greg Montalbano 
(originally intended for the polysix, but seems to work also for the 
MonoPoly).

http://www.kentonuk.com/kenton/retrofit_kits/kgmp-rk.html
Very expensive, but missing clock for the arpeggiator. Also I could 
imagine separate Gates for VCA and VCF Envelope.


Is there any other known interface?

Do you have any experience with one of these interfaces


Best regards, Florian