Vista - Sorting mail by contacts.

I’m keeping my emails sorted by contacts where each contact has its own dedicated folder so I later can quickly find back any conversation with that person. Your “Today’s Unread Mail folder” tip helped me a lot to easily find back any new items. I still like my sorting method but it’s really hard to find back any rules (sometimes my contacts change address) as I really have over a hundred of them now. Also, I feel that Outlook gets slower with each rule that I add. I also tried to mimic my sorting method at work but then I hit the rules limit quite quickly.
Is there any way to overcome these issues without me changing my sorting method?