A fellow MINI owner in our club has an r53 with the oem clear tail lights. Well one of the bulbs burned out. After about 6 months of searching if finally found someone who sell replacement bulbs.
http://www.racinglab.com/
I am sorry if this is a repost but, I wanted to share the wealth.

 

I still dodn't find the bulb that burned on mine. I had one of the top rear fog light bulbs go. single filiment. Red with teh silvery blue coating. I had to replace with a led.

I am ready to find euro spec. red with clear turn now. I am over the clear thing.

 

Thanks for the info!

 

I am not sure of what kind of bulbs you guys are talking about but this site : www.xenonmods.com is where I got my "invisible" lights from. They work great and have been going strong for a bit over two months now

I was a little leary after I had placed my order as I did not eve get a email but I got them in 3 days

 

The r53 clear oem tailights are on a circuit board and are about impossible to find. A fellow SSM member searched and found them off of this website.