I know how you feel. We have 4 separate BES environments, 2 still v4.0 (upgrading soon) and 2 v4.1, with almost 9,000 users across them. We have some inhouse tools to make management easier, but of course with 4 different DBs when users change between divisions they have to wipe.

Haven't even had time to look at v5.0 at all yet.