The way I do this is to use my U3 putty client, and tunnel the portable Tightvnc through that.

Thats why i actually mentioned that you could tunnel tighvnc. I use it to tunnel into home from work.

I can't find the origional article/post/tutorial that I used to set this up. Sorry. But I have found a bunch of other articles.

Please note that my home SSH is set up to only work with public/private keys. by me tunneling via ssh into my home for vnc, I am not really worried about security any more.