Attached Link: http://www.renderosity.com/photos/GAL_200304/GalleryImage391058.jpg

Nope, not at all. Having set up the blend node, you can just change the name of the skin file to have the same garment on top of a different skin.

You can create a MAT file for the result the same way as you would create a MAT file for anything else.

I've never tried more than two layers of blend, but I assumed it was possible. I may be wrong in that, but you can do plenty with two. As for changing the hue/saturation, you can do that in Photoshop before saving the texture.

In Poser you can change specularity on parts of the garment to make shiny buttons (you just need to create another map file in Photoshop/whatever). Can you do that in Clother?

In this picture reflection is mapped to give a shiny leotard. This was actually rendered in Bryce but the principle is the same. Last time I reposted this someone didn't believe that the leotard wasn't a conforming item. But it's just done with a map.