This is a rather old post, but I am looking to upgrade my seat on my Speedmaster and the one that British Customs builds looks interesting:

http://www.british-customs.com/triumph-america-speedmaster-low-profile-get-seat.html

I have heard from a number of folks who like both the Maverick and Corbin seats, but no one who has purchased the one from British Customs.

Would appreciate any perspectives from others who are using it, and if they would recommend it from a comfort perspective.