I doubt that UA is going to want to add more regional jets, no matter how nice the EMB's are... no way they can compete on fuel efficency with oil at $120/bbl and climbing.
I wonder how A380 orders are going, with it being the world's most fuel-efficent aircraft per seat.
Too bad about these planes, they were nice... I will always remember my one and only "business class" flight on Frontier, in row 1 on a newly-added aircraft before they had removed the business seats put in by their last customer.