NaturallyAesthetic

I'm doing the same thing for some programs! In fact, some schools require that you apply directly to the PhD, regardless of whether or not you have your masters. As to acceptance rates of people with only BAs, I haven't been able to find that information.

In terms of encouragement, here are some things I've been telling myself when most discouraged:
If you don't get into a program this year, you can always try again.
If you don't get into a program this year, you can take a year to relax (with 60+ hour work weeks, hopefully!), gain valuable functioning-outside-of-academia-skills, and take time to dissect your intentions and life direction a little more.
If you really love what you are trying to do, you will find a way to do it.
You're great!
Hope that helps, and best of luck!

Another approach:

What do you really want to study in grad school? Modern and urbanism? Then find a program that does that well, and mention in your statement that you've had a wide variety of interests as an undergrad but you've decided this is really what you want to work on. You might also mention something about your experience as a producing artist giving you firsthand insight into the creative process and the physical media of art. (That's what I did--I had a BFA when I applied to grad school.)

I don't know that it's really necessary to try to synthesize all your interests in the statement. Frankly, I think you sound like a really interesting candidate because of all that--if you remain a little mysterious, you might incite their curiosity.

I know that Texas used to have someone in architecture who did urbanism (Alofsin? might have retired), and they're certainly good in modern. Emory is good in African, but it sounds like you're turning away from that. That's also a good place if you want to do African interactions with the west. I think they just made a new hire in modern.