Is there any reason you can't have two batteries and two alternators that share grounds but have seperate positive lines and are independent of each other.. meaning each alternator charges it's battery and not the other.. I would think it would work as long as the circuits positive sides are isolated...??

Yeah

But don't quote me

Actually, I doubt that would work. I can't explain it in words, but it's gonna blow up stuff I think.

IDK, try it

Yeah, that will be fine. The ground is just a voltage reference point, so as long as just the negatives are shared and positives are isolated, they will be fine.

if you put the batteries in parallel, or run true dual batteries, it's advisable to put in a battery isolator to help control current flow between them.

a battery isolator would have a voltage drop that is unaccable for winching..besides I haven't found one that can handle that current load, but I have found relays that can handle a very high current load.