Wow! What a great idea for a Christmas gift. I know my husband would be lost trying to figure this out on his own. I think asking her friends or the dealer where she shops would be great. If this doesn't work, a gift certificate might be the way to go.
This year I have purchased a Bernina 380 and a Brother Innovis NX 2000. I love them both but got more bang for the buck with my Brother. I love that machine.
Good luck! Your wife is going to be so happy.
Merry Christmas