Looking at the wiring diagram for 01-02 LS430 shows the rear cigarette lighter (D-CIG), front (P-CIG) and power outlet (PWR outlet) all operate off the same accessory relay in the drivers side junction/fuse box. Maybe Lexus has made a change in the 03 or 04 model?
The add-a-fuse solution would be good if you can find the smaller type. I've tried the larger type with no success as Lexus uses smaller fuse types. Closest ACC power to the center console is behind the radio or at the front cigarette lighter. The P-CIG ACC + power is on pink wire and white with black stripe -/GND. The chrome gear shift trim and wood console pop up with a taped (to prevent scratching) flat screw driver tip. The wood center console is tricky with 2 clips on each side at the corners. Don't use the console to pry up once you get 2 clips undone. It must come straight up to prevent breaking plastic clips (voice of experience
As for routing wires it can be done. Both the under dash panels come out with a couple screws and wires can be routed to the center console between the carpet and center console leather sides. It helps to remove the lowest center dash part (one with seat heater *****) by pulling it forward. Running wires to the rear dash is very difficult and i wouldn't recommend going thru the center console and under the rear carpet hump (very tight). Instead consider running it down the the door trim.
Oh, I had a Lidatek LE-20 installed on my LS before my Escort ZR-3 shifters. It fits real nice directly under the front plate between the grill openings. It was almost flat with the plate and pretty stealthy. Routing the wires thru the firewall was a challange.