Thanks for your reply. The concerns you've mentioned are certainly valid and I'm keeping them in mind, which is part of the reason that I haven't yet found a piece of furniture to convert. The one I mentioned earlier is a piece that would allow me to make cleaning easy, the material used is safe, allows for air flow, etc... Except that the size isn't ideal. I think I agree with you about 12" not being deep enough. I shall keep hunting for the right piece!