I just added some lights to my soundbar (LED pods from eBay). All I did was run the leads down the passenger side rollbar - along with my speaker wiring - to the footwell dome light on the passenger side, there's little wireloom clips tucked under the door opening on that side that I used to keep it all out of the way (I run carpet-less, the interior is line-x'd). The light is held into the dash with one screw and has a plug on it - I measured my length for the new lead, cut it, pulled the light out, center-spliced the leads from the new lights into the pigtail attached to the stock light, and reinstalled.
I also jumpered the doorswitches to a toggle switch on the dash - basically each door switch button has a wire that brings ground into the switch - when the door opens it completes that circuit and turns on the lights because it grounds to the frame thru the screw that holds the switch on. I ran a 2-lead wire to each doorswitch from the little blank panel to the right of my steering wheel, which is where I mounted the toggle switch. One lead of each wire goes to the doorswitch; the other to the wire that I disconnected from the doorswitch. I mated them together at the little panel, wire A to wire A; wire B to wire B. A to one side of my new toggle, B to the other side. Now, toggle-on, the doors light the domes as normal. Toggle-off, I can run without doors and without having to mess with unplugging the doorswitches. None of this affects the dimmer wheel function, it still works whether toggle-on or toggle-off.