Epic weapons are a great concept and I remember getting my first epic 1.0 in EQ, a great memorable moment. The problem with Epic Weapons is that weapons are very integral to your character and when new content is released they are often outdated by quest/dropped weapons very quickly and then they just sit in your bank as a good memory.
My idea is a storyline quest that spans the level ranges, say starting at level 10 when you tend to branch out to shared zones more, have the storyline quest also act as a content lead on style quest ie, where do you go next to find something to do.
Involve all 3 spheres, a few examples, you have to complete a diplomacy quest to "convince" NPC_01 to give you the next adventuring quest, or you have to help town_01 by crafting a given item or performing work orders to a certain level and quantity or save the town from raiders before they will talk to you(next diplo quest). Convince the town "chief" that you need to form a militia, then convince enough townsfolk to join in, then make their armour/weapons, then help them defend their town against a raid.
After a career(leveling to 50 and doing all sub quests) helping Telon you could be appropriately rewarded with a very nice item, maybe a necklace for each of the spheres involved.
This could help direct players to quest hubs, or underutilised content, and whatever item was the final reward, could be "upgraded" along the way as a less powerful version of the end result, along with an appropriate title for having been so integral to the protection/development of Telon and for bragging rights of course.
As/when new levels/content are released you could simply continue the quest series and upgrade the items further, especially given that you are dealing with a less important slot than a weapon you could make it slightly better than current raiding content, that way raiders will want to do it, as they are normally willing to go to great lengths for an upgrade
You could call it a "chain of office" with appropriate title, like Grand Protector of Telon.