I understand you want a single shield, but think of it this way:
For the price of a Maya, you could get: Tirfing, Alice, Teddy, Anubis, Khal, and still have 10 or so Ads left over. All in all, those cover Medium, MvP, Undead, Angel, and demon properties. When reducing damage; instead of relying only on Mdef, it's smarter to use property reduction. Going to Thor? Fire Armour or Jakk cards. Etc, Etc.
This is more or less what Brahms is trying to say. I don't have the exact calculations anymore since we switched to eA, but I'm pretty much 99% sure that unless you want to run massive Mdef (Gotta Include Gibbet, Etc) just for the fun of it, it's not a viable idea anymore. Also - some MVP's have Mdef piercing attacks now as well.
We're only trying to give you advice though, If you don't like what you see, just pick whatever you want.