'99TL 91k miles
My scenario is as follows:

It happens at random. It's happened maybe 8 times since I got it(2 months).

-Well I walk up to my car unlock the car through remote
-When I try to start it there is no power...no click or anything.
-Clock, radio, interior lights etc are all out. Few turns of he key and car will start.. Or sometimes opening door will cause power to come back.
-Once car is started up clock us reset and stock radio asks me for the code.

Sometimes I have noticed that when parked in car with interior lghts on, the light might dim down alirtle for a second every once in a while.

What does this sound like to you guys?

 

Well I suppose the ignition switch might be a suspect.

There was an ignition switch recall for the 1999 TL. Has the switch in your TL been replaced yet? And even the replacements will fail. My 1999 Tl is on its third ignition switch.

Also check your that your battery terminal connections are free of corrosion.

 

Battery is corrosion free

 

Are the connections tight, including the other ends of the cables?

 

The battery may be bad, because the back-up power for the clock and the radio doesn't go through the ignition switch, so you can't blame the ignition switch. Those back-up power go directly from the battery to the clock and the radio simply via a couple of fuses.

 

Good point, what's the voltage across the battery? Maybe you should have it load tested.