Multi-Premium Theme levels/Domain mapping

Hey guys,

I'm not sure if this is possible but I've been looking on the fourms and havent stumbled upon an answer yet. Is their a way to have multiple level premium themes.

For example, I have Free, Pro, and Elite levels. Free gets non premium themes, Pro gets additional premuim themes, and I would like Elite to get additional E-commerce based themes. Is this possible using pro site or can I get another plugin to make this possible.

Also, I have Domain Mapping installed by can't seem to figure out how to make it a premium feature. I already set the Make for supporter option to 'Yes' but it still allows my Free Blog level I created the ability to domain map. Is there something I'm missing?

Thanks for the help!