Creating "Niched" Packages in Pro Sites

I have a question about something I am trying to do. I had thought to use Pro Sites, but now I don't think it will work. Maybe someone can give me a heads up on an alternative plan of attack if Pro Sites is not set up to do this. Here goes...

I have an idea to put together packages of themes and plugins that would meet the needs of certain niches of users (retailers, bloggers, local businesses, etc) and just let a user “subscribe” to a meaningful package of options based on their specific needs from within one Multisite installation. Some themes and plugins would be available to multiple subsets of users, but some may be uniquely suited to a single niche.

It looks like Pro Sites will only work for a hierarchical progression of features, ie each higher option includes all options in the tiers beneath it. Variable subsets appear to be incompatible with the plugin.

Is there any relatively straightforward way to accomplish what I'm thinking about? Or do I just need to think about several Multisite installations...