My advice to you is use to use an official package, or to adjust your expectations. To me it seems very natural that if I insist on doing a custom install then I should expect to have to write my own .desktop files. If you are willing to use a provided package then the packager has likely included .desktop files for you, e.g.:
Code:
pacman -Ql calibre | grep -e '\.desktop'
calibre /usr/share/applications/calibre-ebook-edit.desktop
calibre /usr/share/applications/calibre-ebook-viewer.desktop
calibre /usr/share/applications/calibre-gui.desktop
calibre /usr/share/applications/calibre-lrfviewer.desktop