FYI, Browns and Wheats ARE Ales. I've heard of pumkin ales based on browns, but have never had one, and had never had a pumpkin based on a wheat before until last weekend, when my GF brought home some Blue Moon Pumpkin that was pretty decent.
I find that the majority of pumpkin recipes are actually based off Amber Ale recipes. My 2010 pumpkin was the AHS pumpkin kit, which is based off an amber. I added two 29 oz cans of Spiced Libby's Pumpkin to the mash, and it turned out tasting like liquid pumpkin pie, which isn't everyone's tastes, but everyone loved it.
This year, I actually did a Dogfish Head Pumkin clone, which is pretty much a light porter base. I brewed back in July, going to keg this weekend. Brewed this one with 60 oz of organic pumkin puree, again, in the mash, then added 3 tbs. of pumpkin pie spice @ 10 min. in the boil.