Denmark joins the HRE and/or is elected Emperor. With their focus on the North, chances are Italy would be lost, but Denmark would interested in controlling the Baltic, and the British Isles. Using the manpower of the HRE, they could easily do so. If the Danes build an ATL Kalmar union and exert control over the British Isles - and those are eventually integrated into Greater Denmark, which would be one of the most powerful Emperors in a long time.
(I like the idea of a Danish HRE)