The way I manage regular contact with specific people is to set up repeating to-dos in Life Balance (the frequency of the repeat is of course tunable -- I do have one daily reminder, and a couple of six-month reminders) telling me "Call so-and-so". It's not terribly complicated, and I'm not managing the number of people you've got, but it gets my job done, and perhaps you can build on that.

I've used @Agendas in the past, but mine is empty right now. I'm more likely to put the item into an immediate call or email message than to store it for later. Also, the ease of the Find command in Life Balance makes it easy for me to find a particular person's name wherever it may occur in all of my next action & project lists, so I rely on that as well.

Hope that helps,

Ambar
http://ambarconsulting.com/