They should appear on all maps [i]I think[/i]. I've fought the Elite Monsters and the final boss after them. The boss gives a bonus stage afterward and there's good drops from it. I got 10% clean slates and other good stuff.

I saw a couple doing the Colossus questline in Leafre.

They dropped a couple of potions and an armour or two, and give extra exp.

I've killed around 5 or 6 elite mobs and one boss within an hour of being at golems. didn't get anything too interesting. a few epic items, a cube shard. that's about it.

So tehy appear on all maps ? What is the best map for my 99 f/p mage to find those Elites ?

I found an elite on the Mutant Pig map and it proceeded to completely own me. I couldn't kill it because it kept one shotting me x_x