I just released a new Joomla 1.5 extension : CB Incomplete Info. It's a module that check if Community Builder profile's infos are complete,.If not, it displays a warning asking the user to  complete his profile. I originally created this module for the Joomla User Group Montréal website and I thought it would be a good idea to make it available to the rest of the Joomla community. For all the details and to download it, go on that page.