Multiple communities - How to tie them together (network)?

[cobradude]

Ok, so I run numerous communities all along the same theme but each aligned to a niche. I understand that many have wondered about sharing user/login information across sites and that would be optimal, but since that doesn't seem to be something that can be done right now, I'm wondering how you all networking the sites?

Here's my idea, though I don't know how to implement:

On forum home, I would like to have a category/forum per community within my "network". This would pull in data (cached for a period of time) for primary forums from a networked site and essentially look like another category/forum to the user and link to the appropriate community (they would have to register if they haven't). They would see thinks like a link to latest post, thread and post counts, etc.

Additionally, I would like to have an overall "network" stats...like combined total members, posts, threads, posts, online (this could be cached).

My thinking is that as new sites are started within the network, that there's cross pollination, the site doesn’t look bare or otherwise non busy, etc.

Anyone know of anything like this?