What you see in the pictures cost me $25 dollars. It would be enough to do the front corners of the cab-over.
Local to me it's Multicraft Plastics. They have three prices:
Walked in off the street
local busines oneses
wholesale
So who do you know? Not that is makes a difference at this point. You can add onto what you have with stove-pipe tin.
Edit: Twice the cost and one-quarter the work. It's
pre-finished on one or both sides.