Now GrizzlyDevil, You asked "Is there an eastern foothills?" Pretty sure the word Piedmont is from a French word or term that means foothills or the foot of the mountains or something similar. I've always heard that the Piedmont ends at the fall line where the coastal plain begins. On a map it looks like The NC Piedmont covers a broad expanse, roughly from Hickory, east to Raleigh, and from Virginia to South Carolina between these two points, but running from northeast to southwest within NC. Got a feeling you've heard/seen this many times, but for a reason I wanted to mention it.
Here, most of us think of the foothills as the counties not far to the east of the mountains, and that's correct. I've heard the term western foothills used, but never eastern foothills, which might be because of our proximity to the mountains...To answer your question, though, I say yes, there is geographically and etymologically speaking an eastern foothills, namely those Piedmont counties just west of the Fall Line/ NC Costal Plain. Granted, it's flatter than what we think of foothills as being but generally some rise in elevation if someone is going from counties east of the fall line to counties west of it.