You want IP diversity I got an answer for that. Swap hosting space with other people who have reseller type accounts. I'm sure there is a ton of people on this forum who, like me have many sites and also have more then one reseller hosting account so they can get their site network up and keep it there cheap.
Just come up with some kind of arrangement to swap a certain number of links for the person who is offering up the site hosting space, give them a free membership in your service with a certain number of link credits per site they offer with a unique IP. Then you can use that site for your high pr society links. Yes, there would be a few details to work out but over all it is a good concept.
I have 2 reseller accounts plus access to another reseller account from a friend. Between us we swap hosting space for the unique IP's on a reguler basis. There are probably lots of people out there doing this. Just figure out a way to market it and some kind of interface to manage it and your gold. IP diversity problem solved.
If you like the idea and do it you can sign me up as customer number 1.
Just make it worth while with the link credit and come up with some kind of reasonable limits for bandwidth and hosting space and maybe the type of site you will place on my hosting space .
In other words don't be evil with this so people get in trouble offering you the hosting space. Try and come up with an all static type site if you can so the server load will be small.
Just use some type of rss feed system to pull in the links and keep it light weight. Don't go off and use some shit like WP or something that will use a bunch of server resources. This way you can assure people they will not get in shit for being a part of this. Once you get a good rep and people see it is cool they will flock to you and sign on.
Then later when you got a shit ton of IP's and loads of sites in your link network you got a lot to offer members who don't want the hosting swap but do want the high pr links.
The average site PR is over 2.8 now. As a comparison BMR is around 1.6. We also don't have a crazy approval process - just put in your spin and you get your links.
It's up to us to keep up the PR, so we aren't afraid of showing you where the articles/home page links are. If PR ever drops we'll automatically move your home page links to a site with PR. And when it goes up you get that bonus for free.
IP diversity will come when we load in the next batch of sites. We need content flowing to keep PR so we haven't fully loaded in the network.
The average site gets 5 posts a day and has 4 home page links - so OBL is REALLLLLY low.
This is the same network that we've been using for our SEO clients for about a year and have had amazing results. We'll send out some case studies over time detailing best practices.