Yet Another Weird Battery Drain Issue :: 2002 X5 3.0

[4reagan]

Looking for a bit of direction on troubleshooting a battery drain issue :: 2002 X5 3.0

Here's the history.

1. Battery light began flashing one afternoon while driving - Had alternator tested "Bad" - Replaced alternator.
2. 1 week later battery was dead one morning - Had battery tested "Weak" - replaced battery
3. 2 days later new battery was dead one morning, charged battery (1 hour) car started no problem.
4. 2 days later (after sitting not driven) battery dead again - not even a tick, no dash lights what-so-ever. Charged battery again.
5. Inspected vehicle; I hear no fan or other noises after car has been turned off for 20 minutes.
6. Tested battery for drain. Seems to drain .6V with car and all systems off.
7. Removed 1 fuse at a time to identify where the drain is coming from -Does not seem to be linked to a fuse.

Question? I have no idea where to go from here to diagnose the issue.

All/Any direction or suggestions are most appreciated.

Thnx All!