Easiest way to use GAL as directory

OK, so I have been tasked with getting one of my clients GAL up to date. Data entry would be the easy part, but what they would like to see is all this information driven by an external source outside of ADUC. The requirements are that the GAL be current, self-service and HR driven. I know that Exchange 5.5 had a tool to allow this and that Windows 2000 and beyond do not, due to AD. Thought I would tap this community and see what you guys are doing to facilitate this. Some Ideas I had are paper forms from HR, JD Edwards export of HR data and a simple Intranet form where they can submit updates, that are approved before updating the AD accounts. One more hitch, they would like the GAL to include non-network users contact info such as company provided mobile phones. Personally I think they are trying to skin this cat the wrong way but I would love to hear what the community has to offer.