Bootstrap hi side drive chips dont let negative voltages...why do they care?

I'm surprised at your reading skills. Did you read the first paragraph on the first page? Especially sentence 3? Where it states the high side works with either a bootstrap or isolated supply? An isolated supply could be the form of a DC-DC converter. But they all will work with them, so this chip isn't anything out of the ordinary.

How about something like this, if you can deal with it being surface mount.