For sale is a cab from a 1952 Chevy (same cab as GMC). It would fit 49-53 and by using the newer rear cab mounts also fit 1948, though the purist would point out little differences like side cowl vents.
It's sort of solid, has rusty floor but not gone yet, some rust behind fenders, and the cab corners are there but not great. Basically it hasn't been messed with so you wouldn't be trying to fix others poor work and not so far gone you couldn't fix it with available patch panels. A better starting point than many restorations attempted in our neck of the woods. Thus the $300 OBO price.
Forklift available for loading. Located outside Lexington, VA