As much as I'd like to visit Yosemite National Park and do some rock climbing...lets just address some things regarding beds right here.

Unless you buy a sleep number bed (which has a full, flat, plastic foundation - and can be a real treat to set up if the molded plastic isn't quite right...:( ), or a small child's bed where a piece of plywood would be enough support, you are probably not going to find one with a fully wooden bottom piece. That's okay because, just like draping a cloth can limit the effects of overhead beams, your box spring and mattress keep the wooden slats supporting them from being an issue.
If your bed is a "Bunk Bed", support slats/beams on the bottom of the upper bed will present a "beam" issue for the person on the bottom. Of course in which case you can get creative with a piece of cloth they'd like to hang above them and over the slats.
Stick with a wood bed, be sure it has a head board, and if it has the big posts, then rounded sides are better, and if you have a canopy cloth on top, don't let it drape too low towards you.
Much Love, Shawn