I actually feel like your event (NYTimes Hackday in December) was pretty good along those lines; I didn't get the feeling that any of the applications had a significant amount of pre-writing code-wise.
There were a couple with projects that were written a week+ prior but we factored that into the conversation when giving out prizes.
Really? There were a couple that I could see that being a possibility with (the Etsy/Flickr guys), but I didn't even consider them as contenders seeing as how they sponsored. shrug