Is there any chance of a Qimage export plugin for Lightroom that would allow printing directly from LR without generating intermediate files, as when the "edit in" option is used?  I find that the LR Print module is inferior to Qimage, and don't like the extra files generated with the "edit in" option.

That is a well known fact   
Many of us don't either so we do the obvious, and use Qimage Ultimate to process and edit our raw files 
Terry.