There easy to get, there jsut expensive, luckily i got the ones out of my fathers old f350, he had 2 150w stobe packs in that beast. I got the strobe heads and wiring from my uncle. My set up new would run like 400+
Whelen Engineering makes the best strobes, there pricey but last forever.
Heres one that would be good for you possibly
http://needlights.com/whs690xxxx.html