I dunno if it's somethin ya'll would be interested in, but as you know powertools often come in great cases, in all different sizes. What may not be common knowledge is many contractors and carpenters just don't bother with them and that quite a few don't even take the cases when they get new tools.
If you have a tool supply outlet nearby ya outa swing by and ask if they have any empty Porter-Cable, DeWalt, or any brand name tool cases kickin' around in their back room, many would make perfect trunks. Not just a hardware store tho, it'd hafta be where the "pros" go to buy their stuff.
I've had my eye on a set of these as panniers;