In a post on the Autopareri forums, a user posted some photos from Alfa Romeo with old scale models and designs for past cars like the MiTo, 159, etc. In those photos are what appears to be a MiTo sprint, with a sloping rear roof. I tried to replicate it as close as I could but I don't think it it 100% the same. I wonder how far along the idea was at Alfa and if there were any plans for it to be released. In those same photos there is also a model for a MiTo cabrio. Below are photos of the Sprint model.
Source: Autopareri forums