i think jorge and dr.bob hit the nail on the head. while panochromatic emulsions could probably be made by the small manufacturer or home chemist, the dyes are very expensive, and the process is a pollution-nightmare.
hasn't kodak been listed for years as harsh polluter?
i guess that might be one of the harsh realities of photo-emulsion manufacturing, and probably one of the reasons why the eastern european + chinese film industry is gaining such ground.
ortho emulsions ( like black magic or liquid light ) are not too too hard to make on your own. ryuji suzuki and others do this sort of thing, quite sucessfully. while black magic and liquid light are very slow ( asa 1 - 6 depending ) it is my understanding from conversations with one of the chemists who works / worked for luminos, that silverprint is very fast - close to asa 100!. it is still available at the calumet website and i imagine it is so expensive because of its relative speed (34$ USD / 8oz).
i've coated thin plastics ( like food wrap + nitrocellulose ) with liquid emulsions before, while it can be done, the non-rigid aspect of the backing/substrate does not make it very easy, and i couldn't imagine coating a whole roll of "film" like this. the emulsion binds well, but the bending/curling causes cracks in the emulsion ( food wrap). if that is the kind of look you are going for ... i also tried to make a "roll" of collodion to put the liquid emulsion onto. it isn't too hard to pour collodion on a sheet of glass, use a pin to pry it off, and carefully cut it into strips. i say carefully, because it isn't safety film, but explosive film. the emulsion didn't bind with the collodion, and i can't imagine sticking an explosive like that into my enlarger head ( B-O-O-M ) ----- >> i'll stick to using dry plates