~/.ssh/authorized_keys:

from="proxy.thimbl.net",command="finger-wrapper" ssh-rsa AAAA...

Very doable.

Based on what tricknik has said so far, this strikes me as an HTML5 WebSocket spawning SSH. Similar to what was discussed here:

http://news.ycombinator.net/item?id=1694607

Great idea, I had awesome .plan files way-back-when and spend most of my time in my shell.

Updating my micro-blog with cat >> .plan ... ^D would be enjoyable. I am looking forward to your work!