GNOME 3.14 UIs
During the last months a new GNOME shell extension for ConnMan has been created by Jaakko Hannikainen that supports GNOME starting from version 3.14. The extension is uploaded to extensions.gnome.org with its upstream repository on github. Also, a stand-alone ConnMan settings application has been created, supporting GNOME from version 3.10 onwards. The settings application is available on github.
Its also possible to run the system tray based UI on GNOME; the system tray works on any modern desktop implementing the freedesktop.org standard. The system tray based UI was created by Tomasz Bursztyka.
In addition to these UIs, Arch linux has an excellent list of ConnMan UIs.