Sazz - not sure of your space situation in DDs room, but one thing we've done to make room for guests staying over is to get the single/double bunks - the ones with a double bed on the bottom. you can store stuff underneath it in the under/bed plastic storage tubs (you can fit heaps in them) and, if you do have guests over, you have a double bed ready to go.

we are in storage hell at the moment while we wait on replacement garage - everything is stored inside. but i'll second/third the notion of plastic tubs - the top of our walk in robe houses seven of them, all of gremlins stuff that will be stored (clothes that are too small, nappies too big or small) will live in the top of of her wardrobe in tubs, we have excess books in plastic tubs (cos we've had mice probs as well) - hell, we even have plastic tub in the bottom of the pantry with cake mixes and pasta in there! cat food, dog food - it all goes in plastic tubs. they stack brilliantly, are mostly rodent proof etc... we've never had any get into anything (and as i said, cat, dog food, pasta etc in them, we even have smelly candles in them and the ONLY smell we get is when we open them - mmmm yummm!)

the initial outlay is a bit high, but if you get quality ones, you can recycle them for everything!