I wasn't sure they even existed until I did an extensive search online. I don't have the supplies on hand to frame with wood and I really don't want to spend the money on them at this point, not to mention...wood frames are pricey! Even the simplest wood frames aren't cheap. Most of my work looks just fine in metal frames and they're so simple to put together.
In my search I found Your Picture Frames, a company which sells metal float mount picture frames(!) so I ordered a sample frame today. I'm not sure what I'm going to get but the description sounded good so I'll let you know what I think when it arrives.