Does structure even matter anymore? Just run a line of black duct tape across the bottom and call it a day!

-- Kane
--

While I would never deliberately mislead anyone, take into consideration that any information and advice provided was at no cost to you.

Dman:
get thyself to the nearest junkyard...find a nonrusted tailgate...remove,repaint or....leave a different color for that 'urban warfare' look.
cheers,
el raidman

the track that holds the rubber seal for the rear deck might be rusted out along the bottom also - you can cut a piece off a parts deck (or off a door) and blind rivet it in place.
bondo makes a filler that's reinforced with fiberglass strands - if you grind off as much rust as you can, then come back with that and sand it, you could achieve a presentable, paintable repair. bondo also makes some red stuff that comes in a tube - you put that on as a last filler before painting. it's cheap and easy to use.
experts do better with it, but I've found that you can't expect too much with fiberglass/metal bonding - it will last a few years if you do a reasonably good job with preparation and application.