You're trying to create a unicorn, or you can keep it simple.
The Buckstop conversion is out unless you want a 10" lift and 44s because that's what they are.
265 or 285 size tires on normal 7.5 wide 19.5s is ok. 285s are at the upper end width wise for those rims though. Plus 285-70-19.5s are 35" tires, so plan on a leveling kit at a minimum up front.
These are not "super singles" by any stretch. They're normal width srw truck tires, but you'll gain 1-1.5" track width due to the drw axle.
Again, the drw to srw conversions your seeing are for bigger trucks. You could do a 10 lug conversion as well as long as your shelling out big bucks, then your options for wheels get more plentiful for heavy duty.
Plus, don't you want the width of a srw? That defeats the purpose of a super single.
American Force may make something that would work as a not so super single, or a 19.5. You'll spend about $1000 per rim but they are all bling!
Now, to put a SRW bed on, remove the front hub spacers and slap on some regular 19.5s with up to 265 tires (285 if you want them to balloon out a bit), is easy.
What your asking about is a very "custom" basically one off setup to gain a sticker and a set of overload springs.
Slap some 19.5s and extra leaf on a srw truck and you walk away with the same thing by removing and reinstalling 32 lug nuts and 4 u bolts.
