Probably not what you're looking for but I get Castrol Syntec 0W30 from either Canadian Tire or in the US @ Auto Zone or O'Reilly Auto Parts. It meets the specifications of BMW Longlife-01.
Lots of people have been using LiquiMoly 5W40 in the US without issues so I think it should be ok.
Have you ever changed your CCV/cyclone oil seperator?
Edit:
http://www.bimmerfile.com/wp-content...hetic-oils.pdf
Edit #2: Google search for your motor (as per your sig) yield this list of approved oils meeting BMW Longlife-01 specs: