I have been buying them for many years on ebay, with excellent results. I recently bought about twenty 48 SMD panels for $1.77 each shipped from China to convert the ceiling lights in our new TT. I have converted several TT's and several tow vehicles to LED's.
Besides the panels, which include 3 types of adaptors, I have bought these two styles and been very happy with them (I know how to use the link creator thingy, but for some reason it isn't working for me right now -- sorry, you'll have to copy and past the links):
http://www.ebay.com/itm/400494607087?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
http://www.ebay.com/itm/Pure-White-BA15s-1156-1210-68-SMD-LED-Car-Turn-Tail-Signal-Light-lamp-Bulb-12V-/371062578001?pt=Motors_Car_Truck_Parts_Accessories&hash=item56650d9b51&vxp=mtr