Hey Jeff - Saw this question a few days back and decided not to chime in, but since no one has responded I'll throw in my two cents.
Let me summarize the problem as I understand it. If you use Marketo's Inferred State data and use a smart campaign to put Inferred State into the State field, it won't work with Progressive Profiling because the fact that the field has any data means it is no longer eligible for profiling.
As I said 3 years ago on the "similar discussion" thread I find the IP lookup to determine city, state, country to be fairly accurate. But no database will be 100% accurate, so you'd like to give the user the ability to change the value to something different if it is inaccurate. That's what you mean by "Dynamic State" correct? That you want it to pre-fill with what the system thinks it is, but allow a user to override it if it isn't correct.
The only real thing I can think is to make the field always shown, but always having State on every form after the data is validated is really strange.
All in all, i don't see a great answer. If you want the data, it can be verified but it can't be progressive. It seems you should accept the data, or not. One lingering thought is that in the very long days of Summit 13, I seem to remember Eric Hollebone discussing it during his talk. You might look up his summit talk to learn more.