I bought the iRig Acoustic Stage contraption few months back, and hey, it is a great idea....
http://www.ikmultimedia.com/products/irigacousticstage/
It works well and I can 'electrify' any acoustic I have that as no pickup, or I don't want it to have a pickup.
The down sides are it is 'good for the money' but not in the Fishman league for sound quality and the kicker....road use major or minor.
I mention this gadget because the idea is great and I hope Neumann or Fishman or even someone like Boss, are beavering away on their high quality, probably expensive, road ready version! The iRig has the idea - easy to mount, and remove, on most acoustics, sep preamp with outboard controls........
But I imagine my Neumann or whatever maker's model to have heavy duty leads, power supply, eq, etc in a sturdy Boss type floor pedal...... and hope it is Bluetooth/wireless!
BluesKing777.