I don't know how easy it would be to do this with KOffice, but using
AbiWord, I've got a very simple bash script set up to do conversion from .doc to .html (with AbiWord) and from .html to whatever (with calibre's commandline).
E.g. save this as
~/bin/docconvert.sh
Code:
#!/bin/bash
filein="$1"
fileout="$2"
abiword --to=html $filein
ebook-convert ${filein%.doc}.html $fileout
Then from the command-line, something like:
docconvert.sh myfile.doc myfile.epub
will convert from .doc to epub.
This could of course be improved a zillion different ways, and can of course, be one of the associated applications for .doc files in nautilus to skip having to open a terminal.