This is something id love to see more people do. There is already the rather neat Dornian heresy, but what would YOU like to see? With an alt-universe you can litterally do whatever the hell you want and not worry about it effecting the canon timeline. Doing something like this would be fun to do as a gaming group if you are bored of canon-40k or you want inspiration for a new army that breaks the rules somehow.

So what would you do?