My 2005 R52S has developed a pretty bad battery drain - it will be dead within 36 hours if left connected.

I have had the car at an independent MINI specialist and he has, at various times:

1 - pulled all fuses and relays
2 - replaced the alternator
3 - replaced the battery
4 - removed the iPod connector
5 - disconnected the EWS, BCM, speedometer and ignition modules
6 - checked all 3 ground straps
7 - checked the steering pump
8 - checked the HK amplifier

He also verified that there is no evidence of corrosion/water/dust/rodents, etc.

We're at our wits end - any ideas?

 

...and your mechanic had an ammeter connected in series when he was pulling fuses and relays? What is the drain in ma when in "sleep" mode?

 

The drain is about 150ma at "sleep." Yes, the ammeter is connected in series.

I've scoured this and other forums and I think we've systematically gone through every prior "battery drain" thread with their fixes.

 

If, as you state, pulling each fuse and relay, one at a time, doesn't eliminate the drain, then there's some device or wire not protected by the fuses or relays that's causing the drain. I would be concerned that a short might cause a fire.