there are going to be advantages and disadvantages to every setup. With your hitch mount idea you really should stick to a winch that is 9k max. I just don't think any hitch setup you produce will be strong enough to be pulling more weight than that. The whole idea of hitch mount is to be able to easily move the winch from front to rear as you need. I also like the idea because the thought of buying 2 winches is scary to me. If you then devise a nice quickplug setup this would be great for most situations you might see yourself getting into.
For me, a winch behind the front bumper bolted nicely to some C channel was the way to go. I had thought about having a receiver front and rear but just didn't think I'd need all that. Again though, the hitch idea is nice since you can pull the winch when driving around town, less weight to be lugging around....well probably not much less weight if you have to build the receiver hitch for the front and the rear.