I'm a noobie at this, but from what I understand, the way to do this "would" be to use kprinter. Too bad it doesn't work with kde 4.x (because it needs a rewrite which depends on qt development that may or may not happen any time soon). I would guess that (qt ...) is the same reason why other kde 4 applications can't do it either.
If you want to do it "manually", there's a great little gui utility called xpp that will do lots of tricks including what you want to a file that's been printed to disk (Print To File), but you have to tell it a bunch of stuff for every file you print.
If you want to live dangerously, I have a project on sourceforge called duplexpr which is a set of shell scripts for emulating duplex printing on simplex printers. It can print from a file or a pipe. I've used it every day for years.
https://sourceforge.net/projects/duplexpr/
The "dangerously" part is that is that it only correctly handles one type of printer workflow - printers that print last page first and face up. It works for HP Deskjet 722 and 895. It almost works for HP Laserjet 1020 and 1006. You just have to flip each completed page over when the printing is done.
I haven't updated the project in a *long* time. It needs a tiny fix to get it to work with the current version of bash, ....
Anyway, if this sounds at all interesting to you, download the package and take a look at the documentation.
Then, if you're still with me, send me a private message or email here or at the project and I'll show you how to get it working.
If someone actually wants to use it, I'll fix it up and put out a new release (not promising how soon).
Joe