We just came from the Coburg service center, great guys. Call and ask them! They do a lot of different work there including collision repair. They're getting ready to do a $100K job on a nearly new '38 Dynasty Jack that went over a cliff along the Oregon coast
. I would think putting in a couple of bunk beds would be a snap compared to that Dynasty!
If not, I'm sure they could recommend someone in the Eugene area that could. There is also an RV outfitter in Bend, OR that does custom work. Google "RV Outfitter Bend Oregon".