We ended up deciding to paint the walls with Benjamin Moore's Yarmouth Blue (HC-150 in Sherwin Williams Superpaint - we had a free can). For the ceiling we used Feather Down (OC-6) in Benjamin Moore's ultraflat ceiling paint. Finding a colour for the accent wall was difficult and forced us outside our usual scheme and into darker, stronger colours.
At the local Benjamin Moore Paint store, we got out chips of our colours and took in our new-to-us tapestry. The designer worked up a scheme for us. To our surprise she went straight to the chocolate browns. We decided to go with "Willow" which we feared would be overpowering, but so far is quite pleasant. To be honest, I think its too dark for the tapestry, but we have a backup plan if we aren't happy with the end effect.
Here is the new look: