My girls have shared a bed (a queen because that is what we had) It is turned so they sleep the short way and have plenty of space between them (it is plenty long enough for them). However, they have started complaining about it.

The inlaws have twin bunks that can be separated that they are insisting we take. I am going to try to L shape them, but our space is so tiny I don't know if they will fit.

I like the idea of a trundle bed.

Sorry, I don't have a good answer, just commiserating!