I don't know why you would want to do that. I think it would be rather expensive, and you give up the streangth of a solid axle, but here is a link to a company that specializes in that; http://www.gocms.com/
From past experience, I would recommend either OX or ARB lockers. They allow you to turn them off when not needed, so there are no handling quirks when driving on the streets. You do pay a premium in the price, but they are both extremely reliable...
You can run a mix of E-85 and Regular gas in your engine. I would not go more than a 50 / 50 mix though. Ultimately what can happen is the the E-85 fuel can rot through your rubber portions of your fuel system, (due to the ethanol) and cause leaks...
I also have a 05 Unlimited, but with the Rubicon package. I agree they are great rigs.
I have been out on the rocks with some of those 4 door JK's. Dang those things are long and can get hung up easy, if you are not paying attention.
I have added ...
I have an 05 Unlimited Rubicon that I have done the same. I used Superior Alloy Axles up front for replacements back in 06 and have not had a problem with them while rock crawling.