You might consider posting your setup on local boards and craigslist you might just find the right guy that is looking to go bigger and he may have the set up your looking for on his rig.
As said before you will be fine with 4" and 35's AT's I run 6" and 44's
The front tractor tires and suspension links were hanging up on the ice ledge. Could not move it with 44,000 lbs worth of winching finally got the ice to start breaking when we put 76,000 lbs on it.