If the manufacturer (my current one was "Made in China") still has the moulds, units should be easy enough to produce. You would need to find out what the smallest batch size is to know how many people to round up. Often it's '000s per run. Maybe they could make less and sell them for a higher price?

Alas, I suspect a lot of people, who had an Otterbox on their N900, probably binned their case when their phone (USB) died, instead of trying to resell on here or an auction site.