The Morgenthau Plan doesn't look possible, in my opinion. If this partition plan also included the resettlement of Germans from the annexed regions (and it would've been ridiculous not to have done this), the number of refugees would easily be doubled. The "Wesergrenze" region is today one of the most populated areas of Germany, and the Dutch government would have needed to expel easily 6 or 7 million Germans, probably more. The French, Belgian, Danish, and Luxemburgish governments would have needed to expel a further 2 or 3 million.

Maybe these numbers would have been balanced out by not giving as much German territory to Poland (in that article's map it looks like they keep Stettin), but Poland and the USSR still receive Bresual, Danzig, East Prussia, and Königsberg, all very large cities. When the eastern territories were annexed it created a huge refugee crisis and it's estimated that the death toll amongst expelled Germans is anywhere between 600,000 and 2.5 million. These would only be increased with the additional refugees created by the annexation of Saarland and the Rheinland. A further issue with such a large amount of territory (particularly cities) being annexed by Germany's neighbors is that many of them probably didn't have the resources- the funds, the manufacturing capacity, or even the population- to fill the vacated formerly-German cities with new residents and rebuild them while rebuilding their own countries at the same time. Poland certainly had enough people to fill the cities they gained from Germany, but they were something of a special case as their own refugee problem was created upon the Soviet annexation of the Kresy region and expulsion of the ethnic Poles out of those cities and territories.

I also think it's likely that President Roosevelt (and later Truman) would have wanted to avoid a 'harsh peace', like what had been done after the First World War, as President Wilson called for a 'just peace' for Germany during the peace talks and was dissatisfied with the harshness of the terms. It's relatively well-accepted now that the harshness of the Treaty of Versailles was an important factor along the road to the Second World War, and Roosevelt probably recognized that.

Bottom line is that, while I can't say for certain whether the main Allies (USSR, UK, US) ever seriously considered harsher plans such as this one, it seems unlikely for them to NOT realize how much this would impact post-war reconstruction and return to 'normal' in all countries involved. And even if the main Allies had taken such a plan into serious consideration, I imagine many of the countries would decline to annex such large amounts of territory, because of the problems it would create for them. Even Poland was nervous to have gained so much former German territory well into the 1960s, for fear of German irredentist claims and an eventual 'reconquest'.