The hardest part of supporting Linux may be in the amount of distro's to support and to solve that issue I would suggest we leverage the openSUSE Build Service for this. That may involve opening some client code but I would think that should not be a too big problem as the iPrint 'magic' is not really in the client components but more in the iPrint server itself.
As a niche player with iPrint I think we should support as many platforms as possible. Think the iPrint client 'engine' would not be too hard to support on multiple linux distro's and most of the work work would be to support the native visible interfaces for Gnome/KDE/Unity (recent versions) etc. As I think we should do this for the 3+ mayor distro's at least and leave the smaller ones up to the community. The engine/service of iPrint would always run on such a platform and allows a user to install command line a printer anyway. So maybe we should split the client in a service that runs on all rpm and deb based platforms and allows command line printer installation and printing. Then have a separate deb/rpm that supports the KDE/Gnome/Unity integration in the desktop the user runs.
A list of distro's we should support at least:
* SUSE Linux Enterprise Desktop (SLED) and openSUSE LEAP: these have the same kernel and enterprise patches - should be not so hard to do (KDE and Gnome)
* openSUSE Tumbleweed (KDE and Gnome)
* Ubuntu (Unity)
* Fedora (Gnome)
* Mint