Quite a few:
Whelen Vortex
Whelen WPS series, specifically the 2800 series and 2900 series.
Federal Signal Thunderbolt 1000T, and just the 1000T.
ASC T-128/T-135, those things are everywhere in my area.
Federal Signal 2001-130
And, on top of all this I just saw a Federal Signal SD-10 today!