Swapping the Gladiator to D60's?
That capacity in a 17" is going to be tough to find. Closest I could come up with was:
- Helo HE878 has a capacity of 3200.
- Black Rhino Madness has a capacity of 3640.
Stock Super Duty rims for many years were rated at around 3200lbs for 17" rims and a bit more for 18" and up.
Alcoa rims were a bit more robust, 3400 lbs I think. You might contact them for suggestions since they work in some heavy duty applications.