Database Information Library Best Practices

Hi Everyone. Looking for a solution for documenting a legacy data warehouse... Contains various types of databases including Oracle, MySQL, MS SQL... Would like something searchable that supports collaborative input... I have reviewed almost a dozen tools with no luck... Now am considering a hybrid approach, maybe model the database in Schema Spy or Navicat and post to a wiki... Problem is keeping the model in sync... Any advice/lessons learned would be appreciated.

-ClusterFailure