Welcome to CPF. Hmmm, You'll probably get a lot of different answers on those two questions. As far as big that can actually be carried somewhere around here there's a custom light that was made which I believe is a 600 watt aircraft style landing light put into a smaller searchlight style housing. That might qualify. As far as more realistic stuff there's HID flashlights of various sorts which tend to be quite expensive - Barnburner 75 watt is one and those are super bright. There's also some customs from fivemega and Mac that make some ~ 100 watt lights - some of which can start paper on fire in about 1 second if they are close to it. But for more realistic real world use lights you might want to look at the ROP or Mag85 customs. Those are all incandescents or HID as first mentioned. For LED pocket carry super bright lights there are also a lot of choices here. Anything with a Cree, Seoul SSC, or Luxeon Rebel is going to be the brightest if they are driven with a high current driver. And it all depends on how much you want to spend and how custom you want it. Look to Fenix, Orb, Novatac, a slew of Chinese lights from various dealers here, Lumapower, Gladius(U.S. made I think), and dozens more I can't think of at the moment. Check reviews section here and
www.flashlightreviews.com (it says closed but all the reviews are still there) for a lot of comparisons.