Warning, possible spoilers.

Just found this out, unfortunately it was AFTER i spent a fortune on getting armorer trained to 100.

Anyway it's during the quest you receive from Umbacano after you sell your first Ayleid statue to a shop. The quest is named "The Collector"

After you've collected about 6 statues for him (could be less, could even be 3 or so) he'll give you a new quest, to find some special aftifacts for him, carry on doing those new set of quests for him untill you reach the one where you must try and purchase a unique Ayleid crown from a woman in the Arboretum district called Herminia Cinna(stays there most of the time, though she tends to wander).

Talk to her to find out that Umbacano is actually not an innocent collector, but is trying to unleash the power of the Ayleids for himself. She will then put forward the idea of finding another crown, genuine but not the correct crown Umbacano needs. Accept this proposition and the map marker will be set for Lindai, travel there and do what is necesarry to get the crown from deep in the ruins.

After you've handed the 'fake' crown to Umbacano, he will be pleased with it and be none the wiser that it is not the right one, which will lead to the next and final quest. He will tell you to meet him in 2 days at the next location (Nenalata), so go there and rest for 48 hours or so and Umbacano and Claude Maric (the guy who previously attacked you)

Enter the ruins witht hem both and fight your way through till the end, where Umbacano will sit on the throne and chant. Bolts of lightning will flash everywhere and you'll find a toasted Umbacano left there. The next part theres two ways you can do it, the easy way or the hard way.

Easy way is, rush and loot Umbacano's corpse for the Crown of Lindai, then lure all of the (creatures vary for levels) Liches out into the open space where you came from, and them run back past them and out of the ruins.

Hard way is always more fun, and it is basically just kill everything then loot Umbacanos corpse. Doing that can be very hard though, especially for a high level character. Killing about 8 Liches at once isnt an easy task.

However you choose to do it, get that crown! it is the key to infinite armorer training. After you're home free, finished the quest and have some time to train, go and buy lots of repair hammers and just go nuts on the crown. It appears in the list of items to repair, but has no health visible... so it wont repair at all but you'll get the exp from it.

Enjoy the free exp! and just to mention this... If you like to steal things, you can go and find Herminia Cinna again and follow her back to her house. Break in sometime she's not in (all day basically) and you can find the real crown locked away in her bedroom! its a nice thing to steal, better than your average silver spoon. Values at about 4,500, its not too expensive but its a nice thing to add to your collection of cool items.