In one of my potential timelines I wanted to create a Cold(ish) War between France and Germany. Basicly France ends up with Wallonia and in the 19th century France and Germany fought a couple of wars over Luxemburg, Alsace-lorraine and the Saarland. This ends in a stalemate/cold War situation. Both countries basicly gather a bunch of nations and lead an alliance against the other. France mainly focusing on the mediterranean and allies with Spain, Portugal, Italy, Sicily, Morocco, while Germany focusses on central Europe and allies with Denmark, Finland, Poland and Hungary.
Personally I think this might work, but the problem is that you still have the Ottoman Empire (which might collapse and then the remaining nations join one of either alliances), Russia (which could simply descent into anarchy or something). The biggest problems though are Britain and the USA. Both wil simply be too strong not to be a major factor in the world. I could see both ignoring the situation in Europe (in my mind Britain kind of leads a lose alliance of neutral state, including Switzerland, the Netherlands and Scandinavia).
The problem with this scenario France and Germany sole superpowers is that if you want to get rid of Britain or England, you need to get rid of them around the 17th-18th century. In that case France rules the continent and Germany won't form. If you want a strong Germany you need to go to the 19th century and at that point you can't get rid of Britain (or the USA). To avoid this, you probablt going to need a POD somewhere deep in the middleages.