I went to leave work and when I put my seatbelt on, the part that attache's to the cab ripped right out out. The rust finally got to it and now I have a hole in my cab . Does anybody make a replacement patch for this area?

 

Which part of the seatbelt came loose? Where the retractor mounts to the cab, or where the stationary lower part of the belt bolts in, (next to the seat mount)?
LMC Truck sells replacement floor pans, but I believe that the seatbelt mount itself attaches to a piece of 1/4" (ish) steel and not to the thin sheet metal floor pan (It bolts through the floor pan but not to it). I'm not sure anybody sells a direct replacement for that part, but you can probably find one at the junkyard and cut it loose, then weld it on to your truck. But honestly if that thicker reinforced piece has rusted through you may have bigger rust problems, so I would take a close look at some other parts of your truck to make sure they aren't ready to break also (Frame, crossmembers, shock mounts, etc)