Rusty,  Mazdatrix sells just such pullys.  I have a set new in the box that I don't need.  Look at the mazdatrix site.  If you like them, I will sell you mine at 75% of their price + shipping.
 
Dave Leonard

    Now that I'm running only the mechanical water pump, I need to
    find an alt pulley that can handle two belts.  A few months ago,
    there were 576 (rough estimate) messages about pulleys for
    alternators.   I can't say I read them all, but I can say that
    I don't really want to go back and read them now :-)   If someone
    recalls a double sheave pulley, that will fit a Nippon Denso Alt,
    and perhaps slow the alt down in the process, that would be
    excellent.  If you don't recall, I can look through the messages,
    but I'm hoping to avoid that if necessary.             Thanks,
    Rusty