Developing Kodachrome is 'merely' following the published patent. Coating it is another matter.
Support can be purchased from the Photographers Formulary, but IDK if they can supply it in the size you want. I have 1 roll of Kodak support given me by a friend who just happened to have a roll at home. I believe it is 100 ft x 5". I would have to check.
It would be a shame if projects like this fail due to lack of the film support or some such detail. I keep running into problems like this involving chemical supplies. The support problem looms on the horizon for me too.