Converting top bunk to larger size

[pmahoney]

Has anyone ever sucessfully converted a small 30" wide upper bunk to a wider one (ie, 60")? Our unit has one of those configurations with the Full bed on the bottom (notched mattress corner) and a 30" bunk on the top. The sleeping area is sandwiched between a bathroom wall on one side and the outside of the unit on the other.

My initial thoughts were to create a cleat / ledge on all sides and then create a lightweight aluminum box frame with internal rails every 10", then line it with 3/8" plywood and then the mattress.

I've already found a few studs on the internal bathroom wall that I could anchor to, but need to be careful because the toilet vent stack is hidden in the middle of the wall as well- don't want to tap into that!

Our kids are getting bigger and if this worked, it would mean we wouldn't have to break down the kitchen table or the jacknife sofa when their friends joined us.

Am I asking for trouble here?