I have a friend that makes ESBs with a lager yeast at lager temps. Surprised me, I thought it was an ale. (Actually, I thought it was a low-hopped IPA)
That experiment depends upon the yeast, whether it colors the taste at all, or has some esters. It could work, but it'd have to be real specific as to what you are trying to determine, as many people already have a pretty good knowlege of different yeasts and how they vary based on ferment temperatures. Like maybe both neutral yeasts, so you'd have the best chance at isolating the effect of lagering.
Here are a couple more ideas in conjunction with blind taste tests --
1. Hot side aeration. Rack half into a bucket, letting it drop through the air, then chill, vs. the other immersion cooled and then racked cool. Or you could whirlpool one hot, one cold?
2. No chill vs.: chilling, whirlpooling and carefull siphoning.
3. Pellet vs. whole leaf dry hopping.
