Following up again on my follow up (sad, I know), here's a Windows batch file that just uses the file association of a file to look up the relevant print command in the registry. So for all file types with a registered print command, it can print it. Then we just have to copy the file to a temp directory on the windows box, launch the batch file with the temporary file as an argument, and delete the temporary file (hopefully it's no longer needed once the print command returns). http://www.robvanderwoude.com/files/printany_nt.txt
Again, the only control over job options here is the printer defaults.

In an ideal world, we might at least figure out if a file with unknown type is ASCII and print it as .txt.

Ironically, a postscript file may require an associated program like ghostscript just to send it to the printer (maybe trying to print as .txt is a really bad idea, in this case)