Am I understanding you correct?
"the only vehicles with this feature [the power liftgate?] are the ones with the auto up and down [window/moonroof] feature. I know the X5, 5 series, new Honda Accord's, and the RX300 have this feature [the power liftgate?]"
I thought only the Lexus RX330 had the power liftgate as an option and the RX300 never had it.
I completely agree about the beep. I remember hearing a Lexus RX330's beep, when either the liftgate or the all-window-down function was activated, and it sounded identical to my 4runner's beep when the rear window is remotely lowered. Maybe we could replace the shocks with electric actuators (I am guessing this is what the RX330 uses) and program the remote to actuate the liftgate instead of the rear window. And as you said, we could use the key to lower the window if we want. One concern that I have is that our tailgate may be heavier than on the smaller (based only on overall vehicle size) RX330, and the same actuator might not be powerful enough.
I will try to look into the mechanical setup of the RX330, as soon as I can.