Theme for main site

I have the Pro Sites plugin installed with the Premium Themes module enabled. I'd like to configure some themes as Network Activated, such as:

Twenty Twelve
Twenty Eleven

However, I am also running BuddyPress, and on my main site I want to enable a special them such as:

BuddyPress Default

I want this theme to only be allowed and enabled on my main site. I do not want it enabled or available on any other blogs in the network. I also don't want to make the BuddyPress theme available as Pro Sites level/subscription because its not something they can buy.

So how do I do this?

For plugins, as Super Admin I can enable anything I want. I see this on the Plugins page:
"As a Super Admin you can activate any plugins for this site."

Can I do something similar for themes?

Thanks,
Casey