I need a mod that disables the main quest is there one out there?

Why would you want to disable the main quest?

Did you get stuck in the water purifier room?

When you use the alternate starts in FWE the MQ doesn`t make any sense.

If you want to play without completing the main quest then couldn't you just ignore it?

A mod like Nerevar Say Nerevar would be good for Fallout 3 I think, because the game world actually substantially changes. Well, it does in Broken Steel anyway. It's probably too difficult to do at the moment, or someone would have attempted it by now.