TL;DR — a native hypervisor is coming. stay tuned.
For the last few months, I've been working on a hypervisor for OpenBSD. The idea for this started a few years ago, and after playing around with it from time to time, things really started to take shape around the time of the Brisbane hackathon earlier this year. As development accelerated, the OpenBSD Foundation generously offered to fund the project so that I could focus on it in more earnest.
See the full story over on the OpenBSD Journal news site.
Re-using the existing connection is of course useful to fend off the traditional killing techniques for rapid-fire password guessers (such as http://home.nuug.no/~peter/pf/... and similar), but you still have to come up with the set of bytes that will let you authenticate. Which leads to the other thing --
The clowns I have been writing about ("The Hail Mary Cloud" -- http://bsdly.blogspot.ca/2013/... and links therein) used a totally different approach, but the general advice re passwords and other issues given in the conclusions apply here too.
If this is timesharing, give me my share right now.