I forgot to mention that you can do about a 4" design with a 9" machine. When you get the to the middle--put water soluble thread in the bobbin & top or by hand--baste the rest of the quilt. Then take it off the frame, turn it 180 degrees (top to bottom or vice versa) and roll it up to where you left off. You'll be using your payout & takeup rollers opposite of the way you started. It's hard to explain but once you see it done--it makes sense and it gets the maximum amount of travel out of the little machines.
You can also just do puzzle pieces, loop-d-loops, little squiggles, etc. all over the quilt and not worry about basting & turning. Many block designs can be broken down into smaller sections so you quilt an entire block like the big machines do but you do it 3-4" at a time instead of the 9-12" swath the bigger machines can do.
The little machines can do most of the things the big boys can--it just takes some creative thinking.