Here's an expansion mod to New Vegas that adds more Legion content. Currently in beta. Could be interesting.
Nova Arizona is a fan-made expansion of the New Vegas main worldspace.
The core principle of Nova Arizona is to seamlessly blend with the game's vanilla content, simply adding more for players to experience. Many quests and encounters are designed to accommodate couriers of any playstyle or faction alignment. There is no main story; everything in this mod is side content intended to support the conflict in the Mojave while further exploring the game's themes and lore.
Although most of our lore is original, Nova Arizona takes heavy (albeit selective) inspiration from the game's cut content, developer interviews, Van Buren design documents, and like-minded fan projects. The Legion in particular has received a total narrative overhaul in order to alleviate some of the common criticisms made against their portrayal in vanilla, which should prop them up as a much more believable faction. Nothing has been retconned from vanilla.