Here's another one that may be obvious:

I like the look of a 5x7 print on a larger sheet of paper. I've been trying to think of a way to contact print a neg in the center of the paper, and keeping the rest of the paper masked off so it remains white. So far my idea is to use an 8x10 matt with a 5x7 hole that I place on top of the glass, and line up the paper and negative underneath it. If I had a dedicated printer for LF, I could tape the matt in place, and mark off boundaries on the foam as to where to place the paper, to keep everything from sliding around while I set up. I only have one contact printer though, and I want to still use it for 35mm and MF contact sheets.
My original thought was to put a piece of paper down, then the matt, then the neg inside the matt, all lined up, and then a 5x7 piece of glass over the neg. Would the glass be heavy enough though to keep the neg firm against the paper for maximum sharpness though?
I am starting to get the impression from reading other posts that my $40 PrintFile contact printer is not going to be sufficient for good contact prints anyway (not sure why- maybe this could be explained? Is it the weight of the glass or something), so I may be having to dish out for another frame. I sure would like to avoid that though.....