Most challenging build in Skyrim?

Are you talking about something like this?
Seems like a pretty challenging build to me.
http://kotaku.com/5867385/hes-level-35-i...is-dragons

This is my current character. It's more a game of patience than "challenging". It does make the game more fun than just hack'n'slash/sneak/etc.

There are cheats to getting around the need to kill things yourself. Since you don't get the kill count unless you deliver the fina blow, you can attack things without killing them or use followers (although follower kill counts will count as yours if they are still under your command). And then there's payin for trainers for level ups.

[video=youtube;tkyxQbZx63w]http://www.youtube.com/watch?v=tkyxQbZx63w[/video]

Stats:

 Spoiler

The hard part is finishing a questline.