Yabedude,
First off, I still owe you money for the fog light mod!! Tell me where to send it!
Anyways, I would be careful about installing a flasher unit into the rear high mounted center brake light. That is generally a "no-no." In the emergency services several manufactures make flasher units that will alternately flash the rear back up lights with the rear brake lights (overridden by applying the brakes or going in reverse), but the unit is only supposed to flash the side brake lights, and NOT interfere with the center high mount brake light.
You could alternately put strobes into the rear side brake lights, or into the rear fog lights, although you would have to drill a second 1 inch hole next to where you drilled the holes to mount the parking/brake/turn signal lights. This also would be illegal, but less visible so less a chance of getting hassled by PD. You could put strobes into the turn signals as well.
Lastly, someone else on this site bought a whelen slimlighter LED (
http://strobeguy.safeshopper.com/80/2181.htm?988) and stuck it on the rear window with suction cups. It is powered by a cigarette lighter plug, so you could run an extension cord to the front or just hard wire it. Only thing is you can't lower the rear window all the way if you suction cup it. (I like sirennet.com too, but strobesnmore.com is my favorite).
Lastly, the colors that we are allowed to use vary by state to state. Most, but not all, allow us to use red lights. In CT/NJ/NY, among others, however, firefighters use blue. Amber (not orange) is TECHNICALLY for work vehicles, plows, etc, but if you have a permit for blue, no one will care if you have amber as well. It is also a "brighter" color and can be seen from further away, thus is a bit safer, plus using different color combinations catches the eye better. I believe legally we can use white as well. In the rear of the vehicle, while technically illegal, most places will allow you to use flashing red lights, esp. if they are "hidden" in the rear brake lights, like my rear-facing strobes are.
Amber is the best color choice to avoid issues with PD. Although most states actually do require permits to use them, I have never, ever heard of a cop asking to see one, no matter the situation.
If you use new LED technology, MOST are clear when off, regardless of the color, which makes things more subtle, and avoids attracting attention. (Unless you want attention and thus turn the unit on.) See my front blue/amber grill lights, mounted below the PIAAs, for example. They look like regular fog lights when off.
Hope this answers all of your questions. PM or e-mail me if you have any other questions about mounting lights to the rear of your 4R. I would be happy to help.