Do they make a tonneau cover for a truck that has a toolbox that sits on the bed?

http://boxbuddy.undercoverinfo.net/index.html

I have a full size undercover on my current truck and it is AWESOME!

Good luck.

I had a friend years ago that had a box that sat above the bed in his truck. He took it to a real upholstery shop. The guy there made a cover that used an aluminum track that he bolted to the box at the height of the top rail on the truck. He attached a piece to the end of the cover that slid into it. The rest snapped to fastners around the bed. Of course it was a soft cover and was custom made but worked really well. If he needed the bed he could roll it up and tie it against the box or slide it out of the track and then roll it up. You would have to find a real upholstery shop to get it done.
I haven't seen a cover that you could go buy and have installed the same day. I think that there are too many manufacturers of tool boxes making too many sizes for that. If you wanted a hard cover you I would think that you should be able to by one and take it to a good fiberglass man and have it modified.
Good Luck!!!

Extang used to make them. If they don't list them you might rey calling them to se if they still do but don't list it.