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.
That's a really good tip, but why would you get that for a carry-on piece? It's not exactly in a carry-on situation that your luggage has the highest risk of getting abused.
For leather luggage these make sense. Perhaps also for tweed luggage and certainly for stuff like Vuitton cases. For ballistic nylon I don't think it makes a lot of sense. BN cleans up rather easily with some soap and a brush.
Till