Our boys share an upstairs room. The room has eves on both sides and not a bad size...however the shape of the room makes bunks really awkward and two twins would have taken up most of the floor space. Our solution was to make built in beds on either side of the room built into the eves. Here is some of our inspiration.
My grandfather actually had a bed sort of like this made by my Great Grandfather in their Craftsman bungalow, a bed that I slept in once as a kid. It's a cozy space much like a boat bunk (I know this from experience with those too)
First we had a contractor on the job... that turned out to be an expensive mistake..they messed up some measurements and wouldn't work around our floor re-finisher's time constraints. They quit and overcharged us for their labor.. we had to contest the hours put in. My husband took over the project and finished the building before heading overseas again. My job was to fill holes and paint. Happy to say that I finished..and after I get the room all painted, curtains up etc. I should have a whole room revel here too.