I'd use the so called "Chico" (WY1056, etc)...
Word has it that it's descended from the strain that the late, great Ballantine brewery in Nj apparently used for their "lager" beer (they used a different ale strain for their ales). It's very well known that 1056/Chico is a very 'clean' ale yeast that makes very convincing bastard lagers.
Kind of ironic, really. Nowadays, the Ballantine XXX Ale that Miller contract brews for Pabst uses a lager strain. LOL.