While I'm not sure this would address your concerns of utmost fidelity, I found the my life became more satisfying when I picked up one of these cheap on ebay:
which someone on this list recommended a while back now, as a very simple way to get my guitar into an EDP, and go from there into the front end of an old tube amp that doesn't have an effects loop. Honestly my ear for fidelity isn't enough to take apart the tonal sacrifice, and my rig has too many holes to worry about noise as much as I would like, but for me, the price was right, and it was SO easy to just put a small, PASSIVE box on my pedal board, and have a very quick, easy, and intuitive routing system. I do still think about investigating some other routes, but for me, this one is passible. Not sure that it will solve what you're looking for, but I've been meaning to make a plug on this list for this cheap device that apparently works by magic.
Eben
