Another great source is Mathew Newsome at Albanach.org: http://albanach.org/leine.html
Based on their research I constructed several Leines for myself, my son, and my wife. I am not a tailor by any stretch of the imagination, but construction was very simple. I dyed a bolt of Irish linen a saffron yellow, folded it over and cut it to the length where the hem would reach my ankles, cut out a kneck hole with a 'V' shape and hemmed it; cut large baggy sleeves that would be longer than my arms; sewed the sleeves to the shoulders; and simply ran a seem up both sides and along the bottom hem of the sleeve. I closed the bell shaped sleeves at the end with an opening for my wrist, forming a bag.
I hike the skirt up with a belt so that it just covers my knees and it is incredibly comfortable on a warm day and can be surprisingly warm when it is cool (especially with a mantle).
I did not sew up my eonar/jacket, but had a woman sew it for me (I did not want to deal with those pleats). Based on illustrations from the Ashmolean Library in England, I asked my wife to do a stitch decoration that would replicate one of the designs. The flowers are an applied wool felt. We are not really sure how the decoration would have been done, so this is speculative on my part. I was quite pleased with the results. This image shows the front:
Here is the back:
...and the sleeve:
Here is the completed kit with leine:
