Kids loft bed with storage underneath-would be good for large bed as well. I love these types of beds, so much storage. I always wanted one when I was a teenager but back then no body made this kind of thing in Canada.
Lofted beds with walk-in closet underneath. Good when you're short on bedrooms for all of the kids. Loft beds and instead of a closet underneath, it could be the kids "rooms" for private and quiet time.