A new QtAda/GtkAda Integration Kit is available, or rather; a technology preview for such a kit is available.
From the website we get this little snippet of information:
QtAda/GtkAda Integration Kit allows to use both toolkits in one application. It makes simple integration of existing GtkAda code into the QtAda application.
Technology preview is available for immediate download from the QtAda download page (see snapshot section).
The QtAda/GtkAda Integration Kit can be used with the latest QtAda 2.2.0 snapshots only.