Following what Island Dog said. The good news on this matter is that you can "easily" import sections via SkinStudio, by open one of the skins

in SkinStudio and then using the feature from: File > SubStyle Management", then on bottom left, "Substyle synchronizing...(Pro only)"

the re you will have a option to select the parts of the skin you want to import.

The bad news is that you can do it importing between sub styles inside the same skin, not between different skins, not at the moment,

I suggested this feature right after read this post. But Remember, involving commercial skins, you should do this for personal use only.

You can set WindowBlinds to use the taskbar and start menu form one skin and the rest of the elements from another skin from within WB Config. Just go to the setting tab, select the taskbar and WB  you want and apply changes.

That's the only "easy" way to combine blinds that I am aware of.