I got sick of my ugly brown camera bag and decided to try my hand at "creating" one. This is an inexpensive purse from Target. I liked that it was fairly shallow, but would have a little bit of width as well, and could "tuck" under my arm rather than have a long shoulder strap.
At the fabric store, I bought a piece of white foam, and about 18" of industrial velcro. I cut the white foam to sit inside the purse, about 6" from the top on each of the sides. I cut out 4 strips of the velcro. I pulled the two inserts (gray in this photo) out of an old camera bag, and attached them with the velcro to the sides of the white foam, slightly off-center. It would probably be clearer if I could take a photo with my camera in the bag. . . . but then I couldn't take the picture! The camera would sit roughly where the pink phone is. Just picture the inside of most camera bags, and then a little bit of foam, velcro, and the insert of an old bag can pretty much re-create a "house" for your camera in whatever bag you'd like! This isn't the way I'd want to transport my camera if I was going someplace where it might get lots of rough treatment, but it works quite well for daily use, especially if I'm only bring one lens with me somewhere.