I think I have a modified Israeli mask (by Cosmic-Ware in K?ln), and I use the same hoses and couplers as my S10 and Russian masks. In fact it seems that the hose threads are univeral, though my British S6 mask has a bush on the mask that prevents other filters attaching (though they will attach to others if needed.
Although it ain't the USA, Studio Gum in Vienna have hoses and accessories. I think SG have an agent in the US, but I don't know the name. Pay through the nose I expect too!