If she has a long arm and 2 other machines, it's going to be hard to guess what she DOESN"T have, but here's something fun and useful, and she probably doesn't have one:
http://www.amazon.com/Solid-Replica-...ds=bird+sewing
It's called a 'sewing bird' and it's great for when you need a 3rd hand, like if you need to rip out a long line of stitches. The whole business clamps to a table, and mouth of the bird is another clamp that holds the fabric.
I use mine all the time (lots of ripping ;-)