I have a GK midi pickup mounted to a Squire Strat and use a Roland GR-series synth that converts everything to midi. I use this almost exclusively to enter chords into BIAB and as a midi controller.

But it's not inexpensive. $ 200 for the GK pickup, $700-800 for the Roland GR unit, unless you find something used. Plus the cost of a steel string guitar on which to mount the GK midi pickup.

Something that has caught my attention lately is this $199 midi guitar controller: "You Rock Guitar"
http://www.audiomidi.com/Products/yrg_yrg1000_kit/
http://www.yourockguitar.com/products/you-rock-guitar

-- which, despite it's toy-like appearance, has had some pretty good reviews.
http://www.soundonsound.com/sos/aug11/articles/you-rock-guitar.htm

I haven't tried this unit yet, but it might be worth exploring.
It has midi out and USB out, 50 open tuning presets and 14 capo setting presets.

John