Good news.
Note that BBB does also make replacement brake pads for the Hayes MX2: BBS-47
See: http://www.bbbparts.com/discbrakepads_bbs47.php
Jagwire makes them as well: DCA052 They are 35% cheaper than the Hayes and the BBB pads but are maybe less wear resistant.
See: http://jagwireusa.com/index.php/products/v/hayes
Other manufacturers of these pads: Kool Stop, Goodridge, Nukeproof and probably some more.