The motorcycle tie-down shown in the pics below is mounted in a Momentum 25G. I do not have any personal experience with the system (and I think the owner hasn't actually used it yet) but as I don't remember this tie-down system being mentioned on this forum...so below are a few pictures. As you'll see, the system utilizes the tie-downs in the floor. If I remember what the owner told me, the company will custom size the width as desired.
Howard
Howard