Quote - A3, H3, Laura, Luke, SP3, D3, The Freak, The Girl (V3UV), & MilBaby3 are all unimesh & can wear each other's textures as well.

Slight correction: A3/H3 use a separate mapping system, for reasons known only to DAZ. You can use their textures on each other but not on the other 3rd generation characters.

Re: skin shaders -- most of the ones I've seen are basically just colors layered on top of the texture to change it subtly. There's some very good packs on RDNA that I know I've linked to before... um.... ha!

http://www.runtimedna.com/mod/filelib/viewed.php?file_id=3778

(Warning! That's a direct download link.) If you surf through their freebies section there's a couple of others too.

Some small samples:

http://www.sunsetgrillcomic.com/index.php?page=cast

Pretty much all of these characters were made with RDNA shaders layered on top of a skin (with the exceptions of Fausto, Riley, Travis, and Tara). Elroy's skin is the same as Travis's. So yeah, you can get a lot of variation out of a single skin by using shaders.