Here out West, a bunch of boats come with swing-away tongues on the trailer to minimize the overall length. That and you can look for a boat with a removable swim platform, if that is available on the boats you're looking at? The other thing to keep in mind is that if you are looking at a boat with a deep V then you might double check the height as well, 6'-10" is actually a couple of inches lower than standard for a regular garage and might interfere with the windshield of the boat (or the boat will hit the garage door if it doesn't open all the way past the garage framing).
I know a buddy who was looking at a 22ft. crownline cuddie cabin and it was 7ft. exactly to the top of the windshield... He just let a little air out of the trailer tires to get it into the garage
Hope that helps