Heavy Duty 20 inch tire?

I have a quick question. Does anyone make HD 20 inch tires? My buddy is putting 20's on his 05 Duramax and regularly pulls some hefty loads. He is needing tires with a higher load range than most 20 inch tires we ahve found. Thanks for the help!

the mich. 52s are a good tire

Goodyear makes the Wrangler AT/S in a 275/65/20 Load Range 'E'