As I think I said on one of your other threads a while back, I am all for another zoo in the greater Los Angeles area. The truth is the Los Angeles Zoo is overcrowded and cannot handle the crowds that come with a population the size of Los Angeles. My city of Tucson has two zoos, Phoenix has two zoos, Chicago has two zoos, and of course all the major twin city metroplexes have a zoo in each of their twin cities (Dallas-Fort Worth, Minneapolis-St Paul, Tacoma-Seattle, etc). My cousin lives in Los Angeles and was recently there for snow day and said the crowds were the worst he has ever seen. And I have seen some horrendous crowds with him myself before, so it must have been almost unbearable.
I am behind you Ungulate Nerd, but as others have stated and I hope you are aware you do need to start at a realistic level and build up from there. Polar bears are unobtainable currently - my zoo has a polar bear exhibit already built and is AZA accredited and were told we cannot aquire a bear to replace the one that died, so we are converting the exhibit for brown bears. Elephants will cause you a major fight from Animal Rights Extremists - look at the nightmare Los Angeles Zoo went through. Still, it can be done, just be ready for the picket lines.
Since your first love is ungulates, I think that is a good place to start. Exhibits for them are easy to build (just fence off a field), they are relatively easy to care for, they are readily available (some species anyway) in the private sector - look at all the game ranches in Texas and elsewhere.
I would strongly suggest you join the ZAA. If you can make it to their 2013 convention in Phoenix this Fall, I think you would make some great contacts. I have not been to one of their conventions myself, but I read a report of the 2012 convention in the Journal of the Feline Conservation Federation (of which I am a member). Seems like a really good networking opportunity and the reporter stated she found a lot of support and comaraderie.