I went through this rigmorol. 22s will even fit without a lift, just depends on the profile of your tyres. the 20s pictured wrapped in 32" all terrains will set you back $3200 if you buy them in Australia. The most common size tyres to go around these would be a 33 if you were looking for a decent all terrain/mud tyre. And yes you would need to do some modifications to get a 33 to fit. Check sringos thread on 285/75/16. They are the same outside diameter as these. I asked a couple places about getting muds or AT in a 32'' and was told i would have to make a special order.
Would still cost you less to buy them from the states even with the import duties...