You've given me a lot to think about. Our garage is not attached to the house - it sits off to one side and behind the house, so its not possible to connect the two.
I've thought about a dumb waiter, stair chairs, etc., but the way the garage was constructed, there just isn't room to put anything like that in. BTW - the stairs are inside the garage.
We have a very small house and the only room I could consider taking over would be the dining room. But that would be a fraction of the size of the room I am currently using and it wouldn't fit my long arm (or much of my sewing stuff period).
I'm thinking the addition might be the way to go, because I plan on spending another 20 or more years in that house. The fact that it would add value to the home is something to consider as well.