About the per site user registration process

Hi.

Since the multi domain plugin is now working, i am bulding my initial WP multisite project, my 4 gamers Wp network with budypress.

And now comes again this big WP issue about per site user registration which is a very very big issue.

I would like the experiment of pro here using big networks (more than 1000 sites)

this is the point :

Lets assume the fantasy game network, concerning WoW, Aion, and so on. One gamer can be part of several game team ok ?

So, he will register on the site of the first team, and then nothing else, with a BIG problem :

- He cannot register on another site
- He can have access to ANY forum on ANY site on the network !
- He will be able to acces to ANY private zone (member access, absolute privacy or other plugins).

In fact, that means that WP is NOT really a "multisite" but just multiusers since sites are NOT independants one from another.

I post a job project about this issue, without answer yet, but this is a severe hack of WP, and having a private developpement is not secure enough for update matter.

So how do you do with that on big networks ? How if I need to register on several blogs on the network, as possible in any blog systems (even WP.COM !!!!) ?

Is there somewhere a plugin a miss ?

thanks for sharing experience, because without that I cannot build my project at all !