coming from the commercial side of LTL hauling with LDTs we never see lawsuits/overload tickets regarding exceeding a truck mfg gvwr or gvwr based payloads. Were not talking HDT class 8 trucks or dump trucks here.
I've always found it odd why its just the rv world where this supposedly can happen and that theory is pushed by some that have no clue (no working experience) what weights are used in a civil lawsuit or how it all works.
But being a opinion based forum/website the gvwr theory rages on....its made good laugh fodder on haulers websites that I frequent (past and present).
Fords F350 srw and GM 3500 srw has many different gvwr packages.
GM 3500 srw has entered the same practice with multi gvwr packages. Just choose the 10000 package for tax purposes if needed or choose the same truck with a higher 11k-12k gvwr.
GM now offers 15 different gvwr packages in their 2500 trucks ranging from 10k up to 11550 lbs. Some with just 50 lb increments. Choose a 2500 GM truck of your choice with a 10k or a 11550 gvwr.
Of course a 10k gvwr 350/3500 srw will have a low gvwr payload stickers...and the same 12400 gvwr truck will have a higher gvwr based payload sticker number.
Some keep pushing the same old tired civil lawsuit/over mfg gvwr non sense.
The OP can add a thicker blocks which will raise the trucks rear a bit. With the soft rear suspensions today air bags or adding a spring or other aftermarket rear suspension upgrades can work.