Roland GK-3 Question

Hi all,
I'm really interested in turning my old strat into a MIDI Guitar with the Roland GK-3. I'm just a much better guitar player than a keyboard player. I also want to use Spectrasonics Trillian for bass lines.
Anyways, I was wondering if anyone knows a converter for this. I don't want to have to pay over $700 for the pedal Roland has.
I've Googled and returned no such results.
Any info would be appreciated.
Thanks,
Robert

You seek the Roland GI20. It is out of production, but you may be able to find one.
http://www.roland.com/products/en/GI-20/