Since preferences seem to be stored on a per-log basis, a way to either copy preferences from one log to another or create a new log with preferences from an existing one (or both?) would be great. Settings can then be tweaked for a specific log as necessary, but common settings don't have to be configured from scratch.
 
An alternative (at least for me) would be M0TRN's suggestion to include an optional "my call" field in QTH profiles and the QSO list, as that's the only use case I can think of right now for multiple logs anyway.