So the children get one each?
We have 3 children, and 3 bedrooms. No chance of getting more/adding more!
Children or bedrooms 
The boys share , they are 14 and 9. They don't get on at all. Our 14 yrs old is very mature for his age both in stature and mentally. Our 9 yrs old , is just 9 ...annoying to our other son. The room is not large, and is dominated by the bunk-beds and computer stuff (my son builds them)
I feel that our 9 yr old never gets any space for himself, a place to invite friends etc...he is a very sociable boy and I think he would really like a place of his own.
Our other child is a four yr old girl.
I'd like to buy a really decent sofa-bed and keep a wardrobe in our dd's room.
Its quite spacious.
I wouldn't miss a bedroom for a few years, in fact I think we would get more space as the 9 yr old would have a room to use/enjoy.
The boys are like chalk and cheese, and I think the age difference is very marked.
Has anyone done this? AIBU to think it would work? I'm hoping it just might? :)