I haven't seen it in many stores lately, excepting Whole Foods at 91st and Metcalf. It used to be carried at Hen Houses as well, and I have seen it in the past at 888 Market as well as some of the smaller Vietnamese groceries in the Columbus Circle neighborhood. So, my best advice is to call around tomorrow when the produce buyers will likely be in the stores with their order boards.
Oh, and there's a smaller southeast Asian grocery on SMP at Quivira (southeast corner, east side of the shopping center) that has carried in when I've shopped in the past. It's under new ownership about a year now, and I believe they now get their fresh produce on Fridays. It's called Siam, but I'm not certain this number works anymore: (913) 268-6058.