Nothing can beat the open source or Free Software community when it comes to re-using the resources instead of reinventing the wheel. Though not everyone will agree as the general tendency within the open source community is to create a whole new wheel to push your own cart. A majority of open source projects are suffering from duplication.
Luckily, we just noticed a great example of such collaboration (or using resources by different competing projects) within the distro community.
Ubuntu's popular Unity shell is being ported to Fedora (the distro which leads the development of Gnome shell and its also the breeding ground of many latest technologies which are used by the rest of the GNU/Linux world). Interestingly developers are using openSUSE's build service to create this port; openSUSE leads the development of Gnome and KDE along with LibreOffice.
The packages are not yet available in the Fedora repositories but can be downloaded from openSUSE.org.
Note: We would like to follow-up the story, so if you are involved with this project you can contact us at firstname.lastname@example.org