Build my own picture frames--for cheap!

The specific project I have going on that has motivated this goal is some semi-formal wedding picture collages, one for each couple on my husband’s side of the family (I want to do this for my side, too, once my little sister gets married, which shouldn’t be for a few years yet). I have in mind that I would like to do it in a multi-layer style such that there are 2-3 layers of glass, with pictures behind each layer, allowing for depth. I did find one such frame at Target once, but for a variety of reasons, it was not the best solution for me. So, my solution is to build them. I will probably get my glass here: http://www.framingsupplies.com/PictureFrameGlass/PictureGlass.htm
and use crown moulding to build the frames. Since each collage will have pictures from 4-5 weddings in them, I am deciding between 20×24 and 24×36. BUT, since these will be gifts, I’m not sure I want to be so presumptuous as to take up a 6 square feet space on my in-law’s walls. :-)