It's not a browser front-end, but Sandboxie is a way to run any browser
in a secure way.
Here's what Gizmo's Tech Support Alert recently had to say about it:
"(It) creates a sandbox environment on your PC within which you can
browse safely. While browsing within the environment provided by
Sandboxie you are totally corralled off from your other parts of your
PC. Any files you download are isolated to the sandbox. Similarly, any
programs that are executed only do so within the sandbox and have no
access to your normal files, the Windows operating system or indeed any
other part of your PC.
....
"This means you have complete browsing security. Nothing you do while
browsing can have any effect on your PC outside the sandbox.
....
"It's a neat solution for safe surfing but there are some caveats.
First, Sandboxie only works on Windows 2000 and later so Win9x users
are out of luck. Second, the system is only safe if you choose the
option of deleting all files at the end of your browsing session.
Third, you have to be constantly mindful whether you are browsing in
the safe sandbox environment or just browsing normally as the two
environments look exactly alike."
http://www.sandboxie.com