As mentioned in the title I'm looking for a tool that puts on a webserver some .html or .php files filled with popular malware like java drive-bys or other browser exploit payloads? Maybe there is something like this in Metasploit or on BackTrack?
The Social Engineer Toolkit (SET) has something like what you ask for.
It allows you to create websites with various attack vectors.
Check out the 'Tactical Nuke' option for a widespread test.
This is found on Backtrack and integrates with Metasploit.