I've got a vision for using WPMU to help me create DIY type websites for a niche market (the horse industry). I'm very familiar with this industry, very familiar with wordpress and themes, and run my own freelance design company specializing in this industry, so I'm confident that if I can get my WPMU setup the way I see it in my head, I'll be onto something here.
However, I'm afraid that MU has thrown a curveball. I want to make sure I'm doing it right, but I'm confused as to which folder themes and plugins go in (the regular wp folders or the wp-mu folders). I also don't know which folder to put the theme for the "main" website in.
I'm going to utilize the "Supporter" plugin which seems to accomplish a lot of what I'm looking for, and have installed it but not fully tested it yet. I'm hoping for the following to happen:
1. Users come to my "main site" (a custom theme) where they get information on what they can do with our company, and how they can get started. They can sign up to pay for their Premium account or go ahead and make a free account. Obviously I want the free accounts to have some form of advertising or something to help monetize them.
2. The themes will be mostly custom done themes by my company, some basic ones for the free accounts and more advanced ones for the premium paid accounts.
3. Again, certain plugins will be enabled for basic use and for premium paid use.
4. Users are able to upgrade/downgrade at any time. If a user has paid for premium plan, and has premium theme/plugins installed, when they downgrade, those are no longer available AND they get reset to one of the "free" themes (something that is set as default freebie). If they are using a premium plan and simply DON'T pay, their website is either "shut down" or goes into some kind of maintenance page that says something like "please visit Support to pay for your site" (I'll think of something better later).
5. Premium plan users can purchase a domain name of their own accord (hopefully via my reseller plan) and map it to their site.
I'm not sure if I covered it all (it's late) but that is the majority of it. Am I headed in the right direction using WPMU and Supporter? What other plugins would I probably need? Which directory do my themes belong in? Sorry for all the Newbie questions but I want to make sure I get it right before I launch. Thanks!