I doubt the factory would make internal mods for you, check that with Adam.
However I have the ES-5 and she is pretty loud unplugged,in fact I have to turn it up quite a bit to hear the amp over it. I don't own an acoustic to compare it with but it sounds good to me.
The difficulty in the hollow bodies, is the set neck, cleaning up the binding after staining or painting and and feeding the wiring loom in through an F holes