Plenty of folks sell replacement sheetmetal.

Lemme see what I can dig up for URLs..

http://www.superscoutspecialists.com OH
http://www.giddumupscout.com CO
http://members.xoom.com/howteron/ IN
http://users.erinet.com/39617/ OH

I have a pricelist from.. hmm.. dunno when.. from SSS.

Half-floors for $35 (L or R)
Front floor w/ lip - $65 (L or R)
Also front body mounts - $55 (L or R)
Floor support "stringers" - $38 (L or R)

I'd call them and confirm the prices, of course!