You could check a salvage yard. I'm sure there are plenty of 4th gens around if you can find one with less-rusted skids.
It's likely that it's mostly surface rust though, in which case you could strip your existing skids down and repaint. I have an '05 and also live in the northeast. Although my skid plates look like crap, they're not really rusting through. Just on the surface (except where the rocks have mangled them lol).
If you really want to go all-out, you could look into aftermarket skids like the ones from BudBuilt. Not sure on cost, but they probably run a couple of hundred dollars. Upside is they could survive a nuclear holocaust!