I just grabbed this information off another post. However, I can vouch for any of it.
Rehorn body shop in Sacramento that does fabrication & excellent work,
Go to Mexico: Took the paint and door off the RV, then drove across the border and into Mexico.
Winnebago suggested a fabrication shop in Eugene, Oregon called Tri-Metal fabrication. They had all the Winnebago drawings and were able to duplicate my doors very closely. Had to have them painted after delivery. Might give them a try.
Their contact info is:
3825 W 11th Ave, Eugene, OR 97402
Phone: (541) 684-9167
2004 Itasca Horizon ISK-40AD, 350HP Cummins 8.3L
75K miles and the best of 3 Diesels I have owned thus far!