Sorry to dig up an old thread, but I know for a fact that the Hartmann covers are made by Carry-Rite in California. Actually, Hartmann asked Carry-Rite to make their covers, then they decided to make their own covers.

Unfortunately, those are pretty expensive covers at $50+ if there is already an existing template, or up to $175 if they've never made a custom cover. The good news is that they give you a custom fit, but the bad news is that they could cost as much as the luggage itself.

I found another type of generic cover made by Luggage Protect that ranges from $24-$30 depending on the size of your bag. I'm thinking about getting the smallest size for my carry-on bag and seeing how it holds up.