There are lots of really cool largely unknown historical events that would make great a historical miniseries. Something dealing with the war of 1812 in detail would be great.
Everybody knows about te Battle of New Orleans, the burning of the white house, and the bombardment of Baltimore but the bulk of the war took place along the eastern USA/Canada border. The greatest single day loss of American lives took place here in southeastern Michigan.
I think a series on the early years of Benjamin Franklin would be awesome.