I think it is really about Hitler's true goals. If, as he had stated, he was determined to create a homeland for ethnic Germans a limited campaign would have been potentially viable. With the Anchluss in '38 and the annexation of the Sudetenland later that year, the only goal left was the Polish corridor separating East Prussia from Germany proper. Being unable to achieve this my diplomatic means Hitler felt forced into military action. Were this is only goal then perhaps he could have had a swift victory forced restraint on the army, preventing any further occupation then sued for terms with the powers.

However this was clearly not his in intention; with the signing of the Molotov-Ribbentrop pact in August '39 dividing Eastern Europe into areas of influence it is clear the Nazi's had more than reunification planned. The subsequent conquest of Poland, I feel sealed the fate of Nazi Germany and prevented any Allied power from considering them worthy of treaty. This is further compounded by Hitler's utter distaste of Bolshevism. I remember reading Panzer Leader by Heinz Guderian where Hitler ask what Guderian's opinion of the non-aggresion pact is. Guderian - considering the possibilities comments that is a sensible strategic move to protect Germany's Eastern borders. Hitler finds this response rather unpalatable, Ah! I have found the tract:

...I was seated at Hitler's right hand...towards the end of the meal he asked me a direct question: "I should like to know how the people and the army reacted to the Russian pact." I could only reply that we soldiers had breathed a sigh of relief when we heard the news of its signature at the end of August. It had given us a feeling of security in our rear, and we were happy to think that we would be spared the two-front war of which we were frightened and which had proved our undoing in the long run during the previous World War. Hitler stared at me in amazement, and I felt that he was not pleased with my answer...It was only much later that I realised how deep was Hitler's hatred of Soviet Russia.

Guderian, H. 2009 Panzer Leader, London, Classic Penguin pp.84-85

This suggests (amongst other more public rhetoric) that Hitler had no intention of limiting his campaign and an eventual part of his strategy was the elimination of the Soviet Union.