http://www.comodo.com/home/browsers-toolbars/browser.php
Ran this through installation in the XP Mode VM, choosing the Portable option during install. I still recorded 423 new registry entries, BUT, copying just the program folder to other Windows installs it is indeed portable -- seems to work fine in XP & win7, with no recorded changes to Windows, so maybe the biggest hassle is installing to a VM or using something like Timefreeze or Returnil if those 400 new entries would bother you.
Now just have to try it out & see how it compares to the Chrome portable versions I've been picking up at portableapps.com.
