First let me say I think you've got a a fantastic husband. Going for a 26" throat is very wise and a 10 ft frame can do a queen size quilt. The Gammill is a great machine and I would go for the computer up front.
Buying a long arm is like buying a car. Negotiate for extras. I don't have a Gammill but I did purchase my machine during a quilt show and negotiated for the add ons. I received the leaders, rear handle bars, 2ft extension (making it a 12ft frame), extra bobbins, extra needles.