The main problem here is preventing two users with the same password from being able to log in as one another, right? Just merge the user name and password and salt in such a way that the hash is unique for every user name and password pair, and completely unguessable through dictionary attack or brute force. For instance, you could add the ASCII values of the characters in the user name and in the pass (wrapping, of course), then insert the characters of the result into every 4th character of a 50-character salt. This is easily reproduced if you know the method used and the salt, but totally impossible to guess or brute force.

Personally though, I'd work more on making sure the database is secure from prying eyes, rather than hashing stored passwords. Storing passwords as irreversable hashes means there's no way to retrieve the password if the password is forgotten, meaning in turn that you need a secondary verification system - which is always less secure and usually fairly easy to social engineer. If you ARE going to make passwords irreversable, make them short (no more than 3-4 alphanumeric characters), with lock-out of IP / user on failure to log in 3 times in a row. A short password is much easier to remember, and pretty much eliminates the need for a secondary verification system.

The weakest link is almost never site security, but rather human laziness and inability to remember things.