Okay, after some creative google-ing, I have verified that the measurement of 14"+ does include the extended bed. So, the under-the-arm space isn't really larger. If you go to the Singer Australia website, they have a downloadable brochure that gives this information.
I also discovered that the thread cutter Singer is referring to in the U.S. brochure is just the usual thread cutter on the left side of the machine that most machines have; it is not an automatic thread cutter.
Anybody want to take guesses on the HSN price? I'm registering my guess right here - $399. This is based on no knowledge whatsoever on my part (LOL) besides what HSN has done in the past.