I think a list of locations would be great.

Something I do think is worth pointing out: Families tend to live near each other, and in terms of the ultra-wealthy, there are relatively few places you'd find them. They just wouldn't spread out all that much, given that they've all remained in the same country. I think you'd see lots of NYC, some New England, and some LA/San Francisco. Probably not much else other than that unless you started to look overseas.

I think it makes sense that if you have a family which is well-known or whose fortune was made in one area, they might travel all over, and have homes in other places, but their 'permanent residence' would usually default back to that area. There's also the whole 'my family has been one of NYC's most important for generations' and so on.