I've just been reading through this thread, it makes me angry that Irish people from the Isle of Ireland have no idea of their own hertiage. The Leine and Brat most likely would have developed into the modern day kilt and the wearing of the Kilt in Ireland would have been as common for the Irish as it is for the Scots.
However in saying that, I feel there is a new cultural nationalism starting to take shape in Ireland, for many years the Celtic Tiger economy was the focus for many people as Ireland had never experienced such wealth for it's citizens. Now with it's decline and seeing what we have lost as well as gained Irish people are starting to look to their past with re-newed interest. The advent of talented Irish singers and dancers and the Irish Governments willingness to consider the past relationship with the Union of Great Britain is a positive one and shows signs of maturity and understanding.
I know a few of my friends who now have kilts, a generation ago unless they were pipers this wouldn't be the case, in time kilts on Irish streets will be a more fimilar sight. It only takes Irish people to have a positive understanding of their past for this to be so, now that we have gotten over the inferiority of ourselves, it is time to embrace the positives of Irishness once more.