Replacement Dust Cover Boot (for Retrofitted Headlight)?
 

The black rubber boot on the back of my headlight has torn, but where can I buy a replacement? I think it's 4" or 100mm in diameter, but doesn't look like a Ford part. Just to clarify, I'm not talking about the ribbed/accordion collar membrane in the back of the factory headlight housing, I'm talking about the dome-shaped one that snugs over the other membrane, the bulb connector, and aftermarket igniter and keeps moisture and dust out if you seal the widest edge with electrical tape. It looks like this:

https://cimg3.ibsrv.net/gimg/www.f15...931793e3ef.jpg

I'll answer my own question for the archives. Supporting vendor has it:
http://www.4x4truckleds.com/rubber-housing-cap-pair/

and also here
https://www.theretrofitsource.com/ac...materials.html