I think I'm a little strange in that respect... my elders MUST have grey hair! I also insist on my elders retaining the hunch-back look... yeah, it's horrid, but I can't stand the thought of having elders that are visually no different from the adults, so I put up with the maxian extreme of elderness.
If a hair doesn't have grey textures for elders, it doesn't get in my game!
It's so easy to fix!
Just use BodyShop to make a "gray" version of the blond hair. Open the exported files with your paint program and "desaturate." Save and import into BodyShop. Close BodyShop and bin with Theo's plugin.