Marco -- It's not as hard as it sounds -- i have done it. Didn't take long. Of course, you have to know a little bit about the materials you are using. Obviously the simplest method is a digital scan and then make a negative on transparancy film -- that will work fine, and avoids all the rest of the screwing around. However, the original poster said he didn't have a scanner. But he does have a darkroom.
Ortho film is available from J&C, and I suspect they are getting it from Europe, so it does exist. I am fortunate to have a bunch of Kodalith in various formats.