When you say "Polaroid", I'm assuming that you're referring to an "instant" film that can be developed on the spot.

I agree that that would be really cool. but I'd imagine it would be incredibly difficult, especially for a positive emulsion.

I experimented with "instant" developing stuff once, using resin-coated paper as the photosensitive material. I'd discovered earlier, accidentally, that a sodium hydroxide solution would result in incredibly rapid development of the image on the paper; I assumed this was due to the incorporated developer interacting with the NaOH and water.

I made a mixture of water and sodium hydroxide, and something to make it into a paste (I do not recall what it was). I sealed this into a pod at the end of a paper and plastic setup that I made, put it in a camera, took a picture, and ran the whole thing through a set of rollers (my old old Kodak instant camera). After about 30-40 seconds, an image was visible, though obviously not fixed.

I'd think that something like that could be done with your own developer-incorporated emulsion, but its just an idea. There's still the issue of fixing the image ...