AB40k Maintainers

I'm not sure if this belongs here, but...

Is it possible to make an army list as two non-"ally" forces, such as necron and eldar. I can't find out how. If it's not possible, with this be an option in the future?

Yes. Go to the roster rules and tick Apocalypse, and also tick "Trusted, Distruted, and Hated Allies" under the Apocalypse Allies section of those options. You can now choose either a Necron list and add Eldar allies, or vice versa, using the Roster > Select Allies menu option