Use the real thing. You can get LED flasher modules for emergency vehicles on Ebay. I got one for like $40.00 for the deck lights on my 1:1 scale truck. You get all the crazy flash patterns. In many cases the output is 12V, so you will need to drop the voltage with some resistors, or use lots of LEDs. There are 2 on there right now, one for about $20.00 with 3 patterns, and 1 with 16 patterns for some more.
Tim
www.tdats.net
Dave Loman
My site: The Rusty Spike
"It's a penny for your thoughts, but you have to put your 2 cents in.... hey, someone's making a penny!"
Take a look at:
http://www.ironpeng.com/ipe/
Does anyone know if there is someone who makes flashing circuitry that simulates the modern day lightbars on emergency vehicles? I am speaking of the newer ones that use high intenisty LED clusters and are abnoxiously bright.