I suggest just getting a standard sized blade in your preferred configuration (mid-grade, ultra edge, etc) - or use you current blade if you are not going to use it anymore - and cutting it down yourself. You will get the proper film for the inside of the blade and you can get it to the exact length you want. An inexpensive miter box and fine-tooth miter hand saw will do the trick. The film is easy to remove and cut with regular scissors (just be careful not to wrinkle it). A paperclip on each end will help to keep it from unraveling.
A
pipe cutter will also work quite well, with no sawdust to worry about.
Source: Just used one to make a custom blade plug.