From zdad suggetion to me -
If you do not get bunkbeds get an aerotype bed for the extra child.
I found an aerotype - look alike bed at
www.target.com
Or
http://www.amazon.com
type in the search box 'Ready Bed'
$27 for a child under 5 foot - use and ditch after WDW
or if you do have bunkbed at the WL - just ditch
(or use if have bunkbeds and a child is scared of the tip bunk after you get your desired room)
Patterns: Miss Kitty, Spiderman, Tween Bratz, Dora jr, Power Rangers, Disney Princess.
Big kids / teenagers -
http://www.walmart.com/catalog/product.gsp?product_id=3661677
Ozark Trail Elevated Air Bed - Twin XL $28
Perfect for traveler and campers who are looking for all of the comforts of a bed, plus the ability to transport easily. Air bed features include: cozy flocked-fabric mattress top; extra-wide openings for fast inflating and deflating; a built-in pillow for bed-like comfort; folds compactly for storage.