An integrated, portable, proxy over secure tunnel browser:http://www.njutrino.com/
Yeah I can't tell what they're using for the browser code either. It does appear to offer probability components.
This one's a little weird. It costs $9.95 a month to use. (The subscription fee is for encrypting all traffic via SSH.)
There's a free 48-hour trial if anyone's interested.
Yeah, I know you could just use Tor instead!
Tor is not very fast and not 100% anonymous/secure and Njutrino appears to rotate ports. I don't know if Njutrino is trustworthy, but in the absence of alternatives, it might be valuable.
I'd probably use Steganos VPN
for real anonymity/security, but I don't think that's portable. Here's a bunch of other tools