My Juki Exceed 300 has 8 inches to the right of the needle and is about 5 inches high. I've done some quilting with it and it wasn't terrible. Just got to practice bunching it up.
I agree that I've seen alot of machines saying they were for quilting that had small harps.
I wouldn't be scared to buy a Juki on line because so many of its internal parts are metal and not plastic. They've taken alot of the features from their industrial machines and kept them in the domestic machines. Juki needs to start paying me for all the nice things I say about them. LOL