I was looking to get a Double Cream JB and see on the website that you can specify any color combination EXCEPT Double Cream? What's up with that?
http://www.seymourduncan.com/custom-colors
http://www.seymourduncan.com/custom-colors
The original Hughes Plastics bobbins only ever appeared in their raw cream colour due to a temporary shortage of black pigment.
Because during the '70's, double cream bobbins came to specifically identify DiMarzio pickups in the eyes of the vast majority of musicians. It became an unofficially acquired mark of the brand in the aftermarket guitar parts marketplace (which was quite small at that time). When other pickup makers (i.e. Duncan) started to come up in the market, DiMarzio officially trademarked the double cream look as a mark of their brand.
Makes perfect sense to me, looking at it objectively; others have a huge problem with it, though.