We just got our RX400H at $500 over Invoice ($5000 below MSRP) and we are in the SF Bay Area.
This is how we got this great price. First I wrote an email listing the minimum options, in our case, White and NAVI, and offered $500 over invoice and said we were ready to pay today in cash. I then went to Lexus and emailed every dealer within 100 miles of us the same email.
I received a response from every one, some didn't have the color and the ones that did would not go that low. Most were $1500 over invoice and one was $1000 over. However, one called and met my price over the phone. The cool thing is that there was no haggling.... If ther couldn't do it, they said so, if they could then they followed through.
Hate to tell everyone this "secret" way of getting a great price, but when you go to Lexus Dealers, one thing is very clear - there is ALOT of money being made by the Dealers!