The noises I get (just like yours) come from the driver side rear "C pilar" if you will. At least that's where it sounds like it's coming from on mine. Next time I go into service I'm going to mention it. I know it's not the trunk partition on my car, it is in the cabin for sure. I think it may be something behind the black cloth headliner. At least in my case...
2009 E93 335i | Jet | Black Dakota | Grey Poplar | ZPP | ZSP | ZCW | Step | Paddles | i-Drive | CA | Sirius | HD | Logic7 | 06FL | 06NF | PDC | OEM Alarm | LUX
Retired: 2007 E92 335i
Retired: 2006 E90 330i