I have seen a number of mods that look like they are adding ships and such but i would like the see en entirely new system where there are two new factions, the Humans and Covanent who are battling around a huge halo (like 60K around the star) with all of the ships there. The piller of autumn and The truth and reconciliation battleships. Also Foehammer and Banshee style ships that are the normal fighters. If you have the game you could look on the DVD to see if the modle is there.

But this would be the best mod for me, you could also have a small 343 flying around, that would be funny.