http://jamorigin.com/docs/midi-guitar-fo...
True MIDI guitars have separate conversion for each string, so there is no confusion about which string is producing a note or if two strings are fretted to the same pitch.
I have an MG-510 - that's basically a Japanese built Strat clone with a full six channel MIDI converter included. They seem to go for around ￡400 (which is about what I paid new 20 years ago).
eg.
http://www.ebay.co.uk/itm/CASIO-MG-510-M...
If you look closely in the pictures you can see the extra line of pickups just below the bridge humbucker.
You can get add-on multichannel converters, but they cost about as much as a MIDI guitar.
eg. http://allyouneedmusic.com/catalog/Shado...
