lagering has been a learning experience for us, as we've never had problems with ale yeast even during the warmest weather.
We're trying a new tactic. This weekend, we're planning to brew a bunch of uncrushed grain into ten gallons of Märzen/Oktoberfest wort. To compensate for potentially dead yeast, we had five packs of Wyeast 2633 - Octoberfest Lager Blend rush shipped a few days ago. I pulled the activator packs out of the fridge and have just broken the internal yeast nutrient pouches. I'm letting the yeast proof at room temperature for a few days to see which are still alive.
I figure: at least one of those suckers must have survived. If they all prove viable, they'll be divided between two five-gallon fermenting buckets. If only some of them are still kicking, they'll contribute to a yeast starter (lagers should be pitched with more yeast than ales.) If none of them survive, we're brewing a porter or a brown ale and holding out for lagers until it gets cooler.
Further news as events warrant.