I thought I would link up my quest (which is currently featured for the Foundry Contest), I believe it too be the best in detail you can currently find. It did not perform well in the contest ( I couldn't collect the reward even if I were to win it btw ), but that's mostly due to the community voting method in my opinion.
Here it is, it's long, it's huge, it's detail capped... and it's fun if you're here for D&D.
If you can find a quest with anywhere near the detail and size, or even the scope of the plot... please let me know. To date, I cannot find a single foundry quest that compares to it.
It is long, and challenging the first time through it.
"I attack the darkness!"
Foundry Author of Arselu'Tel'Quess (NW-DDQ6P4IKQ)