For your consideration:
This is a lovely Donegal tweed suit by Patrik Ervell from the FW 2010 collection. It has functional buttons (maybe horn, I can't recall), slim cut, and excellent feeling materials.
It's been worn ~15 times. It's in excellent shape. I am too fat to pull it off.
Note that I got the sleeves shortened by exactly 1 inch and the pants hemmed. So be sure to read the measurements carefully.
Here they are:
JACKET (flat on a table):