Where to buy Western style (orange) pumpkins in Bangkok

Does anyone know where to get an orange pumpkin in Bangkok? I don't want to make a jack-o-lantern but it would be nice to cook with that different style, and it seems they should be around now.

The obvious places would be the higher end mall grocery stores, in Central World and such, but I won't spend a lot of time travelling around Bangkok looking just for that, and I'm not going to spend imported food prices on a pumpkin to cook with just because it's slightly different. I've bought other types of pumpkin in Isaan before, traveling, so they are grown in Thailand, but of course they typically only sell the Thai or Japanese versions in stores here.