The Benjamin Moore website states that Lenox Tan goes great with Hampshire Grey or Grey Mist. They also show a navy blue color with it but that would probably be too dark for the hallway. I think that a light sage green color would look great with the tan color and is a nice hallway color.

2 possible solutions/options.
1 find a grey/blue in their color offering that is just right, although way too dark, meaning that is goes with both tans. Then using that too-dark color as the starter find the very lightest shade on that chip, and use that as you foyer. Add in a little more color [double formula? maybe] as needed.
2 blast it out of the water from an opposite-the-color wheel rich deep purple or something wild that just sets off the whole house. I was in a bay front house on the Chesapeake once and the lady had a stairwell painted in a fantastic purple that just made the house. Your color might not be quite so bold but try thinking outside the box.

Not sure if you're still looking, but we just tested out BM Silver Half Dollar for our entry and hall and it is a nice blue/gray.