99 prelude stereo install?

hey i got a 99 prelude and im installing my after market flip out deck and i cant find any constant power running to the head unit, only an ignition switched wire. and im not really up for running one from the battery cause the firewall is a b*tch to get through. i know theres power going to my 4 ways switch, can i steal power from there or is the relay box for that before the on? haha any help?