I've heard rumor that there is a lost tribe in Japan, and another in India, there is still another rumor that a tribe is in Africa...I think it was Ethiopia. I've never heard of the Ireland connection though.
There is a lot of theories flying about.....
there's even one saying that the Prince of Whales (Charles) is the legal descendent of king David.
Here's one for you, but please, understand that it is not necessarely my belief, just posting it for you information http://www.gnmagazine.org/booklets/US/scythians.htm
See the blue links on the left for the preceding and following chapters.
Dan – The tribe of Dan is not mentioned in Rev 7:5-8. The tribe of Dan was omitted because that tribe was early devoted to idolatry, and continued idolatrous to the time of the captivity. Of that fact there can be no doubt, for it is expressly affirmed in Jdg 18:30; and that fact seems to be a sufficient reason for the omission of the name. As being thus idolatrous, it was in a measure separated from the people of God, and deserved not to be reckoned among them. Some references say the tribe of Dan was extinct at the time when Revelations was written, which was around 95 A. D. The tribe may have been so divided by then that it was thought of as being extinct by some. However the decendants still exists today. They were sea people. Today descendants of Dan show up in Ireland, Denmark, and Wales mainly.
Jdg 18:30 30 And the children of Dan set up the graven image: and Jonathan, the son of Gershom, the son of Manasseh, he and his sons were priests to the tribe of Dan until the day of the captivity of the land. KJV
The tribes of Israel were decendants of one of Israel's 12 sons. Not much is known abouit some of the tribes. These have been refferred to as lost...just meaning little is known about them. Most of these tribes were devoted to idolatry. This may be why litle is known about some of them.