There's another work-around I've been using for 6+ months now. A cronjob which resolves the CNAME target (i.e., the ELB hostname) to an IP, then dynamically updates the A record(s) for the zone. It's a hack, but it does the job.

The uncoolness in most hacks like this is they can accidentally create a single point of catastrophic failure. If your cron job fails to run for a while, your entire website will go down.