Sounds cool. I could see that being another fun progression quest like the charms and such, whereby at each rank of the quest you are required to defeat an instanced Fabled boss that is very, very challenging for the solo player and bot group at their given level. You could have 20 or 30 stages over the course of level 1-70, with the final result being a class specific item of massive quality.
Kind of like a solo epic quest without the running around, the crafting, etc. Just a thought!
- Aristotle