And failing that, the Koolflight BEC works great and stays cool even under heavy loads (and tested well). The cheaper ones of the same current capability are usually based on the same circuitry as the KF one, but they don't out out exactly the rated voltage and tend to heat up more under heavier loads specifically due to their smaller size.
Thought I'd post a follow up to the single battery part of the thread. I finally got some pictures over the weekend of a couple of good jumps. As you can see, she flies pretty level. Normally the only weirdness that happens in the air is caused by operator error.