There is a def advantage to IP diverse incoming links.

Why are you spending time asking webmasters to trade links?

You need one way links that will leak PR juice and bring in the traffic from the sites your interacting with.

I would setup a profile account through News Corp and interact on thier blogs and forums. All the different blogs are spread across the country and host different IP's. You also have the advantage of tapping in on thier customer base which is well over 7M+ unique loyalty daily.

There's others that you can do the same thing with.

Grab all the .edu that you can. Spring break is coming up and you could position a travel site very nicely.