The first idea... a way to search for topics '
posted' by a specific user, has been discussed before (and shot down). It's still a good idea, and would love to see it some day. (/me winks to
Zuni)
As for the second idea, just do something like
JW310 mentioned. I did so in this post
here (and then bump it if you feel it's necessary). ~ mind you, I didn't solve the problem, but the idea is still the same.
Use the tools Zuni gives you. They work pretty good!