From what I understand, the 4 year programs at the NUI Universities will be only for Irish students. But I'm not 100% sure about that.
They don't have much of a reason to take foreigners into the 4 year program at any NUI school because they can charge the Irish students full fees, they have plenty of applicants, and they desire to train more doctors who will stay in Ireland. Irish students do not pay for their first degree. That's why the Irish (well, the 4 NUI schools) take 50% foreign students. Taxes alone aren't enough to put an Irish student through an expensive medical education.
Oh, I heard that a 4 year program is starting this year at the University of Limerick. I get the feeling that the other schools are watching that one as kind of a pilot. I know UCC is planning to implement a 4 year program sooner or later. Not sure about the other schools. But I wouldn't count on any of those programs accepting foreign students.