I had to wait a while for one for my XD... but dang if it wasn't worth the wait!
Serpa rocks... even the paddle attachment is great and I dislike paddles.
I have a drop-leg mount for it as well... for backpacking and hunting.
Blackhawk might be able to tell you. They used to have a request link on their website where you could let them know you were interested in one... they don't make them unless there is a large demand.