Hi jawa,
I can be wrong, but is there such reason to be banned by Google? I have done some simple SEO readings and so far I haven't came across such information.

In fact, if you have noticed, web hosts especially Exabytes & Emerge do sponsered some projects. If the projects were on the same server, they should use the same IP instead of each site using their own dedicated IP. Now, I assume all the sponsered site has interlinking back to Exabytes/Emerge because it is a sponsered project. If that is the case, why didn't I see either the project or the sponser's site being banned?

Last but not least, I came across an IT site that has quite good PR. They have a few network sites linking each other on the same IP (except for one) and so far no problem.

Please correct me if I'm wrong.

Thanks.