alot of high end SPL woofers are not made in a 10 inch sub. for many reasons, 1 the size of the motor can some times be larger then the cut out of the driver. 2 the mechanical limits of a small diameter spider would limit the throw, 3 the 10 driver purposes alot of issues and clashes when building a SPL or high throw driver, they are commonly special order from companies who are willing to do so for a experienced competitor in a cone area limited class im not sure if any of those reasons are why FI does not offer one.. but i can tell you those are most common with other builders.