I have used 3 lights as front strobes. All are too bright for full night time use, but they are:
1). PrincetonTec Switchback 3 in strobe mode - great blinking pattern (2 short, 1 long), very bright, wide angle
2). Huntlight FT-01 with Cree XR-E - 100hz strobe at 140 lumens, can be seen 1km away in daylight
3). LED Logic Striker-VG with SSC P4 - 100hz strobe at 200 lumens, collimator for max. throw

For nighttime, I use a helmet mounted Planetbike light with a slower strobe and 4 5mm leds and a wide beam pattern, in addition to one of more of the lights above.

I have tried the PT3 and the Striker-VG together. Cars refused to shut off high beams when I was coming towards them with that combo.