Oddly enough that is something I have been considering.
I was watching the RV 2004 show the other night on HGTV and saw these mammoth motorhomes, which also had slide out rooms. I said to myself "self, why does something that big need a slide out"?
I thought that would be much more useful in a small trailer. Imagine pushing the wall out just two feet, then you have more than enough room for a queen size inflatable mattress.
First I considered the whole hyraulic slide assembly the big boys use. Then I went to a company called
www.bayslides.com , but that was still too heavy and expensive.
I saw that a couple of the early homebuilt camping trailers had slide out bunks. Basically the same as great big drawers. I have recently bought a couple of early magazine articles (actual paper articles) from Ebay which have designs like these.
When I get them I will scan them in and convert them to pdf documents which I will post on my website at:
http://www.forgottenclassics.com
I am probably going to go the simple route myself, and end up building a 5x10 teardrop with a dinette table and booth that converts to a queen size bed.