Jim,
I finally tracked down a set of 6647-H1s through Sean Lorenz of Lorenz Industries. I ordered them in August and got them in September (3-week wait). Try him, as-well-as Off Road Warehouse (ORW), Shockwarehouse, and E-shocks.
Lorenz Industries and ORW, at the time, had the best prices. Even if backordered, they seem to get priority over other suppliers. PM me if you want to know what I paid when I purchased the front and rear 5100s.
Dwayne