The sibling bed: 2 little ones in a twin size bed?

[counterGOPI]

This winter we will be welcoming baby #3 and I am thinking ahead to our sleeping arrangements. Right now my soon to be 5 year old sleeps in her own bed, and my 2 year old sleeps with us in our bed. I love the idea of a sibling bed and so does my oldest (especially after reading 'my 1st little house books') but we can't afford to by another bed until we move out of this sadly expensive state (Oregon) in about 3 years. I was thinking of maybe pushing my 5 year old's twin sized bed up against a wall and putting a bed rail o nthe other side and letting my 2 girls sleep together in that. What do you think? Would that be too small for them ot just right to keep warm in our cold, cold nights.
TIA for help!

[friskykitty]

I think it will be fine. If nothing else, they could sleep with their heads at opposite ends of the bed. Little ones tend to curl up like little balls anyway.