Edit: I just realized this is in the 1500 section... My apologies. However, I will leave my post. I know there are more INGO light vendors also. I just don't know about at the 1500.
ledwarehouse is on the forum, and you get a discount for being an INGO member. I've bought two lights from them in the past and only found out after that you can get an INGO disc out so I'm am trying to not let you make my mistake. Never the less google them and check them out. Also you may check out amazon, from time to time there are deals to be had, I just got a sweet deal from a sale on a G2ZX for one of my rifles!
At past 1500 shows there have been several flash light vendors, or vendors that carry flashlights amongst other items. You will find Surefire, Streamlight and Elzetta that I know of and likely other brands too. Prices are gun show prices (good and bad deals to be had).
Speaking of surefire, I was wondering if anyone knew where I could purchase the old led style foregrip light for a remington 870. I don't care for the new style. Thanks