although sadly: http://en.wikipedia.org/wiki/Hushmail#Controversy
We have a new + faster + easier-to-use webmail coming in the next few months. It's a huge improvement over what we have now.
Search is still in the current folder only though, so that might not be quite what you're looking for.
(btw if anyone wants to help us build a better webmail, we're hiring PHP devs in Vancouver)
although sadly: http://en.wikipedia.org/wiki/Hushmail#Controversy