Michelin and BFG make a lot of tires of different types and no reason you need a ST (Special Trailer) a truck rib will do just as well. The hard part is finding a small 15 (205-225) in load range D or E. If there were room for a modern 30" diameter tire then there would be no problem, I could even use the same 245/70R17s (2205 lbs @ 44psi) as my tow vehicle.
The problem is the wheel well and axle limitations of the TM make even a 27" tire chancy without a lift kit though with a 2" lift, a 30" tire should clear.
Personally I'd go the other way & mod the wheel well for an extra 2" of clearance.
In fact a bolt-on kit with 5k axle, wheels and tires with better load ratings, & raised wheel wells (just needs a 2" band added, easier than tubbing for drag tires) I'm going to SWAG at $1200.
I have wondered a bit ever since I saw the tag on the side of mine advising tire inflation 5 psi over the maximum. (note the LR C in the left sticker)
ps just noodling a bit but
this looks like a likely candidate axle - 3700 lb rating, same spindle, 35 deg instaed of 22.5 degree down angle for a bit more clearance.