I think nutserts are the best way to convert the panels to bolt on.
I've used nutserts of various sizes to construct metal cabinets etc. and have been really pleased with the results.
Nutserts we once a product of Textron, but have recently been taken over/bought by Avdel.
You can buy nutserts at the better nut and bolt specialist sellers. The manual application tool is pretty reasonably priced. Link below is for a data sheet shows one of the nutsert breeds.
http://www.acument.com/avdel/products/datasheet/tsnutsert_9658_mm.pdf