Heated floors would have been the first and best solution, but that's difficult to retrofit on a concrete floor. Second best is to plumb in a couple of powered circulation ducts, even if you have to encase them in soffits. They will pull the heat down from the ceiling through the ductwork and exhaust it at floor level. Third best option is to put back the ceiling fans. The fourth option is to use the portable fans, which as you've discovered, is noisy and unattractive. Fifth best option is heated slippers and an extra sweater.

Are you adding trim molding? I like color on the ceiling, esp if it's vaulted. So I would paint manchester tan on all but the accent wall and continue it up around the angled part of the ceiling on all sides. Then paint the accent wall the greenbrier beige and paint the flat part of the ceiling the same color. It would look great if you have molding to break up the areas painted in the simply white to offset the areas. That may be too much for you so you can just paint the simply white on the flat and angled portions of the ceiling and then paint the walls manchester tan with the greenbriar beige accent. I'd suggest going to houzz.com and searching on tray ceilings so you can get some ideas of how they are treated with paint.

1. I belong to the school of thought that says crown molding should be a consistent colour throughout your home. Unless you have a lodge or cabin-type home, painted white, ecru, etc. is usually best. 2. Varying colours of white or varying strengths of paint on a vault or on the tiers of a tray ceiling give it an interesting depth. I personally don't care for tray ceilings that have some of the tiered surfaces or the sides of the tray painted with the wall colour or a contrasting strong colour. Just my opinion. 3. If you're considering painting the walls a darker colour at bottom that fades out towards the top, I can only assume you don't have a very formal dining room, although the dimensions you give would belie that. Your room size is nice and large, and a chair rail would not box anything in---it is really what one expects to see in a large dining room. It also allows you to "logically" paint one colour below the rail and another above. Good luck with your room!

Paint the end wall. That's actually a very modern look, quite popular right now. People are taking out attics all over the place for a higher ceiling/higher utility bill/less storage. Painting the ceiling and leaving the beams wood is also trendy at the moment.