Mike,
how about a B4E, all three made it to 1940, and their looks remind us of earlier C&S times. One of them would look very nice on a double-header with one of your heavier engines. Or even B4D #69, for that matter, would fit the same role. If you're not modeling past 1943 then the Army hasn't taken away 69 or 70 yet.
Cheers,
John
John Greenly
Lansing, NY