Well, I did try to put a post here that a) explained I was having a similar issue and b) showed how I responded. However the moderators removed it, as it had either a "suggestion or feature request". I think what I posted was actually relavant to the community so I will try a variant of what I posted before...
I also experience this issue. It is reproducable. I have tried all of the listed solutions to no avail. I've tried various software that tries to disable the power button functionality, but this apparently cannot be done in Mavericks. (e.g. powerkey)
I type a lot - and quickly. I use several different computers besides my MBA w/various sized keyboards. The "power" button is very clearly in the "zone" where many other keyboards place "delete". Because it is not flush or recessed - like in the older Macbook Pros, it's extremely easy to hit even if you only partially overshoot the delete key. I have large, long fingers so this is frequent for me. As a result, I'll regularly crash my system, often while in the middle of writing something, which means for several apps that I'll lose whatever work hasn't been saved or autosaved.
This is NOT a user issue - this is a minor design flaw compounded by a software issue, and possibly a hardware issue. For Apple service staff to tell anyone that they're "using their computer incorrectly" when encountering this issue is unacceptable.
I sent an email to Tim Cook, which flagged the crash as well as the customer support issues mentioned here. My prior post had the email text, but I'm guessing this is what the moderators considered a "suggestion" - although I had mostly posted it as a reference in case others wished to also send him an email. His "public" address is easy to find with a google search.
Good luck... I'll be checking back here in hope that someone learns of an upcoming fix for this issue.