Andy Nichols, the QtWayland maintainer at Digia, shared a status update on this Wayland component. QtWayland allows Qt applications to run as Wayland clients natively within Wayland compositors. The only dependence is that the compositor support wayland-egl. Within QtWayland is also an experimental QtCompositor API for implementing Wayland compositors within Qt.
Where things stand now, QtWayland 5.1 sort of works but there's known issues with window decorations, resizing OpenGL windows produce sync issues, mouse cursors only work on window decorations, and menus/pop-ups don't move when moving the parent window within Weston.
As for QtWayland 5.2, plans include the QtCompositor API support allowing developers to implement Wayland compositors with Qt/QtQuick that are compatible with any other toolkits supporting Wayland clients and not depending upon wayland-egl support but also provide for hardware integration plug-ins.
QtWayland 5.2 plans also include a window decorations API to allow for new customizations, window decorations using Wayland sub-surfaces, Wayland input methods integration, and continuous integration tests for QtWayland.
The status update can be read on the Qt mailing list. More information on QtWayland is available from the project Wiki.