a) e-mail our own Rollie at sales@rollieelectronics.com with your needs is what I would do first. He has Sanwa stuff that isn't listed in his sell thread yet. Very responsive.
b) whatever you do **DON'T** try and order from Himura, he ripped me and lots of other people off, I've never seen my parts or money back from him. His site will likely come up in a Google search, why I warn you.