On the latest GeekBrief TV episode (#27), PortableApps is quickly mentioned. They talk about an external harddrive and "heading over to PortableApps" and putting Thunderbird and Firefox on it. They bring it up about three quarters of the way through.
I thought it was pretty interesting. You can download the episode here.
Thanks for the heads-up.
Sometimes, the impossible can become possible, if you're awesome!