This is part of some work we did for a client last year; I emailed it to the author of this project, but it's not been merged into the code base (as far as I can tell); hence I'm uploading it for others to use as they see fit.
It adds :
a) Support for hashed passwords with salts (should convert non-salted/hashed appropriately)
b) Adds support for an uber admin which can add/remove other admins
c) Adds a history table, which logs activities (e.g. user x created survey y, user z took survey a etc etc)
It might do a few other things, I've forgotten now.. anyway, I hope it's of some use to someone.
(Note: I had to edit the patch to remove some stuff; it seems we didn't add a Smarty template page for the history browsing which was not themed for the client, so this isn't included)
Diff taken against v1.8.1