I have three books on Inkscape, the third edition of "Inkscape Guide to a Vector Drawing Program", "The Book of Inkscape" and the smaller "Inkscape for Vector Graphics". None of the three mention the Render tool "Perfect Book Template" which I am reasonably certain came in with version 47 or perhaps earlier. With version 48 the barcode generator choices include two that are useful for book covers, EAN 13 and EAN 5. With these enhancements Inkscape is not yet a complete stand alone book cover tool (no CMYK, no PDF X/1-a) but it is getting close. With a little help from other free software such as Scribus the potential is exciting.
I suggest that as these three books are republished the potential for creating book covers be acknowledged and the "Perfect Book Template" be at least mentioned. It more or less replaces my effort shown here: http://wexfordpress.net/template.html While my program only generates the dimensions and the guide positions as numeric output Inkscape actually creates a true template which can be saved as a pdf and used in other programs like Scribus (or even Gimp.)
The workload can be split between Inkscape and Scribus in various ways. At one extreme only the template is taken from Inkscape, imported into Scribus, and the external page dimensions fitted to the imported pdf or png file. At the other extreme all of the creative work can be done in Inkscape and the finished cover imported into Scribus for conversion to CMYK and saving as PDF X/1-a where that is required or desirable.
I am only beginning to experiment with these combinations. As my experience grows I'll share the results. The next edition of my e- book listed below will have both Inkscape and Scribus in the title.
Stay tuned!