I have to throw my vote for a quaich as well. I recently got one for myself and love it. It looks great on display and has been used appropriately a few times. My quaich looks similar to this

Some other good ones can be found here http://scottishkilts.net/store/celtic_quaichs.html
Another idea to go along with the quaich is as Todd suggested, a pin (if he were wearing a kilt) and a hip flack or as I did for my groomsmen a tankard with an engraving on it.

Quote Originally Posted by Caradoc
It doesn't absolutely HAVE to be older than 12 years.

I've had some rather fine single malts that were between 7 and 10 years old -like the Ardbeg 10 Year, or the Speyburn 10 Year, or even the Loch Dhu 10 Year (and, yes, I'm aware that the last is akin to blasphemy.)
Don't forget Laphroaig 10 year....of course, I have a few 15 year old malts that a REEEEEAAALLLYYY nice.