How are you wrecking so many lighting boards?
If it is the bulbs, you could try fastning the board to a heavy bit of wood, which would damp some of the vibrations.
I have thought about using LED bulbs for a bit of extra brightness, however the cost is a bit high at the moment, and just replacing the bulbs still leaves you open to corrosion.
A while ago I found a pair of fully integrated rear LED lights for approx £60 and was tempted but am not towing enough to justify it..