Several have been made...mostly as drama albums.
One of the things I like about Macross is that it's a future history, and yet (unlike, say, U.C. Gundam...which, by the way, I also love), it's not completely bewildering. In other words, it's huge, but not too huge. Macross Zero was a nice enough revisit, I don't think we need "The 08th Destroid Defender Team" (which would, I'm sure, be a thirteen episode OVA. You would start with 143 major characters, and in each and every episode, twleve of them would get shot, blown up, mashed by asteroids, left behind on Mars, etc. until there's no one left...except the plucky main character, who in the final episode, gets to drive the brand-spanking new Orguss Valkyrie...and gets blown up).