The 1500 euro fine for a RD used in many European countries (and confiscation of V1 plus possibly the car) make this a risky idea.
In France, there is a device (now also an app for iPhone and Blackberry) called Coyote that is really ingenious. Combines GPS plus GSM/GPRS data to instantly log all radar/laser encounters - as soon as a driver spots police and presses a button (one for oncoming lane traffic, one for traffic in your direction), the location is burst to all other units. In France there are several hundred thousand users. The unit also displays how many "scouts" are ahead on your particular road, how close the one ahead of you is, and their "reliability". It is a brilliant system and it also warns of traffic and accident prone areas.
Now to up their game, there are new camera/radar units being deployed in France that operate over a stretch of road and read your license plates and average your speed. On one stretch of the A6 there is a test-bed working and it will flash your license plate on a huge electronic board along with "too fast". That's the test - when it gets operational, you will probably come home to a second reminder with a fine.
I think the GPS units are good to have because they can be set to sound an alert at 1km/h above the speed for the particular camera that you are about to pass - that way you can, without having to take your eyes off the road, go at the exact legal speed.