I have searched for the ellusive trub cone since day one. Only gotten it once, seemingly at random.
I first tried the "stir like crazy and let sit for 20 minutes" method, no dice. Then the "use a paint mixer and drill, then let sit 20 minutes) no dice. I built my version of "jamil's whirlpool IC", no dice. I installed a whirlpool port on my keggle for use with my pump, and after some trial and error got it set up so it makes a real nice whirlpool while pumping. Only once with this last method did I get a trub cone. I THINK it was when I didn't use whirlfloc either. FWIW, I've tried all of these methods with and without whirlfloc.
I did a brew yesterday. At flameout, I added my flameout hops, and left it to whirlpool at about 185F, (chilled it slightly, then killed the chilling water). After about 20 minutes, I turned on the chilling water, chilled it to 68F, still whirlpooling. I let it go for a few more minutes, then shut off the pump to let everything settle. Once again, upon draining the keggle, no trub cone.
I've pretty much given up on the whole thing. I think all you bastards are enjoying a big joke with "oooh, you get a trub cone", and it's really impossible. Damn snipe hunt. I've never noticed off flavors from getting break/hop material in the fermenter, so the hell with it.