Faster evolution
Interesting, Nick!
Perhaps exoplanets around more unstable stars (than our own sun) or more dynamic exoplanets (than our own) might produce something akin to life (or very different from it) that evolves very fast!
Perhaps what we would be searching isn't so much life (as we know it) than something that evolves.
I just saw a documentary about the search for ETI. One suggestion was looking for swarms of artificial nanobots.