Hi William,
There are some really good ideas there- definitely worth looking into a competition of some sort to get links... Problem is most of our audience are currently our clients who already link to us, or use our IP (hence the fundemental C Block problem).
We're looking in to the C-Block problem, as it seems the high performers on the SERP have an array of IPs for their clients sites, looking through their portfolios.
Hopefully I can find something along the lines of Open Site Explorer which can also include server IP, so that I can get some good statistics on where we're at, but I'm thinking that's doubtful!
Thanks so much for your help - this forum is an incredibly useful resource!