I think R & D is the reason that small boards dont cost less. The Speed Special sells in small quantities c/w other SB boards.
If your chasing top speeds, it might be worth while thinking about swapping your F93 for a 86 slim. Also, a close-out deal on the iS76 (81 litres) would be a good option.
If you want to keep the F93, consider the W49, the W44 feels much smaller than the W49 and for some, it will be to small for open sea sailing.
Another option is the iS50 speed that Ian designed. The iS50 was great on rough speed courses and could cope with rough sea states better than most speed boards. AA once used it at Defi in nukin winds.