I've heard the Janome Gem is a good lightweight machine for taking to classes.
Another option, if you have dealerships nearby, is to stop in and ask about small portable used machines. Some of the older (not so old as Singer featherweights, though) machines were quite good.
I picked up a delightful 70s machine (can tell it was the 70s because of the colors and flowers on it!) that is small and lightweight in its own carrying case for something like $20 at a local thrift shop. It would be perfect for taking to classes (something I don't do much anymore).
I also have a featherweight and a 301. The 301 is really too bulky and too heavy for me to want to take to quilt classes, although it is a wonderful heavy-duty machine.