I am trying to find a way to wire some interior lights, so that they will only be on when the ignition key is set to "on", but turn off when the ignition is started, or 1-2 seconds after.

The reverse of this (lights on while car is running) was simple to do, but I am not sure where I should splice the + line to in order for it to only work while set to 'on' and not running.
Are there any devices already wired to do this, that I can just splice some new cables to?

 

nope, cant think of anything that would. you could get a oil pressure switch that diconnects when there is oil pressure