I printed out the area list (excluding area explores). Then I went thru that and tried writing down all the mages I could think of in that area. Then I went and killed most or all of the mobs, and I managed to find some that way.
The next thing I did was go thru my area list again, and I wrote down all the places I could think of that had mage type rooms (e.g. labs, classrooms, summoning rooms, etc. etc.), and I managed to find some more.
Then I put together a list. Then I began trading information IC.
With every mage character I've played since doing this, I've always managed to find at least two out of three. And whichever one I cannot find, I just get the limited wands in its place.