The SunBonnet Sue quilt sounds really cute. I had a SBS quilt when I was a child, made by my grandmother. As to building a stash. I always buy more fabric than I need, whatever I am making. I have built my stash quickly. I get a lot of my fat quarters at Wal Mart. They have a nice selection (not great, but nice) and you can get them for 99 cents quite often. Look on the "sale" counters for the 1 and 2 dollar a yard fabric too. Just be sure to check it good. Some of the fabric is not worth even a dollar. Other pieces are worth a lot more. They have a lot of ugly fabric there, but occasionally I get lucky and find some good stuff. Hobby Lobby has some very nice fabric too. Most start at about $6 a yard and then their fabric is always 30% off the price marked. So you can get some good prices.
Sorry to ramble so, but I just wanted to let you know. As for asking them to cut 1/4 yard off of 20 different bolts. When I worked at Hancocks, I loved doing that (if we weren't too busy). I was always curious about what the ladies were making. Have fun!