I still think it's something simple.
My Ranger is the same way - sits in the driveway and mopes almost 90% of the year.
Jack it up, spin the wheels. Could be brake drag, even if repacked the bearings could still be needing replacement, hub out of true, etc... I'm sure you know the drill.
Are you certain this isn't coming from the engine? Heck - maybe your tensioner is shot or the power steering pump is going out (or running dry)?