I had some, ok a LOT, of free time to waste today. So I spent several hours of it trying to find someplace to get ties such as you requested. Sadly, it was for naught - none as Gaeilge. The best I could find, of ties anyway, was "Kiss me, I'm Irish." (Blecchhh....)
I fear that, for a tie, you may have to find a silkscreening company - preferably a very small one - or art shop of sort and have one custom made.
Oddly enough, there happens to be one just a few miles from me. Screen Printing USA - 'no job too large or small'. 145 S. Main St. Pittston,PA 18640. E-mail contact
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Or Ph: 570/655/1784 - ask for Maudeen.
Unless you got something closer to yourself.