Just brew a regular Oktoberfest/Marzen and use a clean yet low attenuating ale yeast. Or try the California Common lager yeast, or even Saf-lager dry yeast. They can ferment acceptably at ale temps. You just want something that will be clean and accentuate the malt flavors.
Still try and go as low as you can though. At least the mid 60's. Use a swamp cooler type setup. Or submerge the carboy in a tub of water and add ice blocks regularly.
I think you can get close enough if you keep it clean and malty.