Once again, Kat, you are asking for more than Nielsen believes they need to provide. You (the listener) are not their customer. The stations and the ad agencies are.
Those customers do not care one bit about where the boundary is. They are not clamoring for an "interactive map". And if you think about it, whether or not a specific community has any number of PPM panelists is proprietary information that Nielsen is decidedly
not going to make public.
I know it's unintentional on your part, but your suggestions go right to the heart of why Nielsen only makes the 6+ numbers public.
THEY WILL NOT DO ANYTHING THAT UNDERMINES THEIR BUSINESS. Releasing 6+ numbers does them no harm. Not being specific to the public about market boundaries and numbers of respondents not only does no harm, it protects them.
And you know what curiosity did to that mythical cat ...

Wouldn't want that to happen to the real world Kat.