Cubes,
If the hub is warn you may also have some other issues at work here.
With the bike on a stand, grab the rear wheel (front and back) and twist back and forth.
From what you have described you should get movement (wheel bearings)
Look at the spokes and check for movement there also.
Now take both hands and push / pull together, and look for movement in your swingarm. If the hub has been "Out" a while the swingarm will have been taking an extra bit of banging also.
Forgive me if you have already done this stuff, "but the ankle bone connected to the shin bone" kind of thing. I had this going on with my XR, It wasn't as bad as you describe at the hub,
however I ended up replacing the swingarm,linkage and shock bearings also. Merry Christmas!
Tuck\o/