This is one of the projects I'll be working on when we get the trailer out of storage...
I spoke to one service shop that said the most expensive part of it is getting door or drawer fronts to match, as you can go right to the manufacturer if you want it to look stock. Found a great thread in another forum, where the poster had made his own drawers then ordered the fronts, and used metal drawer slides... was pretty slick. I can't remember if ours has framing with thin panel facing or if it is particle board, or plywood with covering. The post I saw, his material was 1/2" MDF or similar, so it was pretty solid once he cut the drawer opening.