All your "must-have" requirements are fullfilled by the heterogeneous enterprise backup solution from IBM called Tivoli Storage Manager.

1. It probably has the best cross-platform support out there of any of the major backup solutions.
2. It preserves permissions & ownership.
3. It has a centralised RDBMS based server console (with SQL support) and a separate GUI-based product called Integrated Server Console.
4. TSM provides several different options for open file backups (it calls this "serialization").

Update: I second Bacula as an open-source solution.

Niel