927 bulb is the same used as the high level 3rd brake lamp on the IS, also known as T15 (thanks to aztecbandit/bulbman for info from earlier post).
http://www.lexusownersclub.co.uk/forum/ind...showtopic=47954
The only site I found selling decent LED replacement for this bulb type is from:
http://superlumination.com/906.htm
I believe sparkystav may have purchased from them before, so check with him for more details. There are some other fancy bulbs from that site too.