Pamperme

Is there a way to prevent the interior door handle and foot well lights from dimming when in drive? I'd like them to stay bright while driving. It adds to the interior lighting ambiance.

Jabberwock

Generally extra lighting besides required instruments inside a car being driven in the dark will significantly decrease the driver's night vision. You may be able to change cbest settings on the LS430 to alter duration on inside ambient lighting but I'd be surprised if a setting allowed it to stay on permanently. Search cbest settings in the forum for more info.

eggtart

you could mechanically hardwire them to ignition power and put a switch in-line. Then you can turn them on/off as you please.

BMW/Mercedes/Audi have accent lighting in the door panels that stay constant on. Its a nice orange or red glow and really does add ambiance to the interior like the OP says.

Lexeffect

This may seem like a good thing to do initially. (Novelty). I think however, that one would become fatigued after some time behind the wheel with the lights on. Just my opinion.