I want one of those types that fit onto the top mattress on the bed (not the actual trundle) so it is long enough to hide the fact there is a 2nd bed underneath. I think the proper name is a valance sheet.
Oh, I see. I have a valance on the box (divan?) part of dd's bed, so that it drapes down and hides the trundle, but the box is slightly longer than a standard divan so the valance doesn't hang well. Does the job though. I got it from John Lewis.
Our trundle is a full-length single bed, which is why the box is longer. The two mattresses are the same length. If yours is shorter, so that the top mattress is standard length but the bottom one slightly shorter, then a standard vallance should fit fine.
Having the valance under the top mattress means less laundry, and that all the children's fitted sheets are interchangeable.
The ones prettycandles refers to (platform valances) are a lot easier to manage. You can just add a fitted sheet on top. Even if your bed is a non standard size, you can hide any excess between the mattress and the base.
Ah marriednotdead a platform valance is what I currently have but cannot use anymore as the top part of the bed is not a box shape but is slatted and then there is a built in headboard so I can no longer fit the valance on. It is going to have to be a valance that fits onto the mattress but because the bed is higher up to accommodate the trundle underneath, I don't think a standard size valance sheet is going to do the trick. IYSWIM!