I just purchased the switch from a European BMW parts department for about 82 EUR ($110 USD). Here is the web site:
http://www.online-teile.com/bmwmc/pr...eit-licht.html
The web site is navigable even if you read no German. If you use PayPal to check out, as I did, the web site zeroes VAT and does not charge shipping. Only a few minutes have passed since I have placed my order, so I may receive an email from the dealership telling me that they made a mistake by selling the part to me without VAT and shipping, in which case I will report back to you that this did not work so well. Please find the order receipt attached to this post as proof that it seems to have worked, so far.