I bought this one and it works great, saw it advertised on another site and there were some independent reviews on it when i googled it that made me buy it
http://www.canadadrivesafe.ca/index....od&productId=4
here are the reviews i found, there may be more.
http://www.buymeaniphone.com/2009/03...m-transmitter/
and here:
good luck in your finds!