ADOD Synchronization – Anyone out there doing this?

I have a customer who wants to keep his Mac OS X Servers in power at his individual schools, but would like the school ODMs to sync up accounts (and their passwords) to a centralised enterprise AD. The sync'ing should be bidirectional. I've tried to find answers on the web without much hope. I've seen a few projects look at doing this with OpenLDAP, but they all seem to fall flat at some point in the past as though they gave up. Is there a metadirectory solution or something for this? Or is the best advice just to give up and go with AD? The Mac servers will definitely be kept around for MCX. Thanks in advance.