Have you given any thought to the possibility of providing this synthetic population on a finer grained basis? It could be extremely useful if this were available for, e.g., each U.S. county (or even something smaller than that).
Edit: I noticed that each person has a lat/long location. So maybe a different way of framing my question would be, at what level of geographic granularity does this reflect differences in the distribution of the various characteristics? And, assuming that it reflects sub-national variations, have you considered allowing a random agent to be selected within an arbitrary geographic area?
This, again, is really really interesting. When it comes to the fine-grained U.S. data, we may be approaching if-you-dont-build-it-I-will territory. :)