barretthunter:
They might have offered Ulster to what was still then the Free State, but Free State resources, even if they agreed to reunification in these circumstances, could hardly have coped with keeping Ulster in order and the Germans would have wanted some key naval and air bases.
The Germans were working with some members of the IRA - see
http://en.wikipedia.org/wiki/Se%C3%A1n_Russell#Arrival_in_Berlin_May_1940, but there were elements of the Irish government who were in negotiations with the British - see
http://en.wikipedia.org/wiki/Irish_neutrality_during_World_War_II for more on that.
My guess? If England fell and the Irish were offered Northern Ireland exchange for being "mostly neutral" then the Irish would have taken it. They had no reason to fight Hitler - which is why they never entered the war (even when the British tried to bribe them to do so). They would have ended up in the same boat as Spain and Sweden - neutrals during and after the war. Or maybe Vichy France would have served as a model?
If the Germans did occupy Ireland, then the Irish would have yearned for the days when the British were there. The British (mostly) had a rule of law while German occupations were rules of terror. One that turned the average citizen against the freedom fighters.
A German soldier dies? Then pick 10 people at random and shoot them. Another German soldier is ambushed? Pick 50 people at random and shoot them. You don't want to risk your wife/children/parents/friends/etc picked at random to be shoot? Then you inform on the guy who's attacking the Germans. Yes, people hated the Germans for doing what they did, but the fear generally outweighed the hatred.
Goodgulf