But... just how quickly? Well, here is the challenge I propose that I doubt could probably ever be achieved even with a full group of 8 (but please, prove me wrong).
Kill as many enemies as possible... with a single scroll of berserker's insight. The one that provides a 300% boost of experience, provided you kill an enemy every 30 seconds. Not limiting it to the size of the group, hold the book for aggro if you want, I could care less. The only rule is that the scroll must not expire. Keep track of the number of enemies you kill, or simply compare your experience total to when you entered to when you stop, and post it.
I think this would be rather difficult given a few factors. Firstly, you will need a path that will allow you to jump from mob to mob without much delay. Not only that, but if any of your builds are too energy dependant you will not have much time to rest which could cause a slowdown.
So, any opinions on the feasibility of this... and if not, good luck.