Ben, I got the tires from this guy on eBay
http://www.ebay.com/sch/bergers10/m.html?_nkw=&_armrs=1&_from=&_ipg=25
I used the super singles on the LoneStar and the front floatation tires for the trailer. I did a WIP on this build that's in the on the work bench section. Let me know if you need more information.