I would like to mount a rack to my seat, that can hold a small cargo bag that will hold a lunch bag and a few tools and other small items. My bike is home built, as some of you may know, and my seat is fairly small, 15" long and about 7" wide. I could wear a backpack, but I wear a vest with a reflective patch and the backpack would cover the patch if I have to ride at night and I also find wearing a backpack uncomfortable. So I'm asking if anyone has any suggestions of a small rack that could bolt to my seat (no problem drilling holes) and hold a small cargo bag. If the bag and rack come together, great. If not I can find a bag.