Prosites plug in options…. is this possible?

I am looking to build a site which is basically a hosting platform, using WPMU. The ability for members to purchase various levels on a monthly basis offering the following…

What I am after is the ability to have 5 levels of product.

Level 1 would be a free account with limited 250MB space, 2 basic themes and basic plugins like jetpack (basically a site that people can use to see if they like the platform with only ability to have 1 subdomain)

Level 2 would be the starter package, giving 1GB site space more themes and more plugins still with the ability to have only 1 subdomain.

Level 3 would be the advanced package giving 10GB, more themes and plugins but with ability to have 5 sudomains (without having to repurchase for each subdomain).

Level 4 pro package, 20GB, more themes and plugins, 20 subdomains (without having to repurchase for each subdomain)

Level 5 Elite package unlimited space, more plugins and themes, unlimited subdomains again without having to repurchase for each sub domain AND being able to map domains.

I have been going though the pro sites plugin for days and cant see how this would be possible with the plugin but wonder if i have been missing something.

Is that only something that could be done with custom changes to the plugins core or is it something thats not possible at all?

Would be great if someone can advise me on this.

Thanks in advance and as always…. you guys rock