George Glen

George was brother to both Thomas and Alexander and he also made bagpipes, although few examples have surfaced up to this point in time. 

This practice chanter is stamped Geo Glen and this bagpipe, which is also stamped with the maker's name.

No doubt other sets exist however the challenge may be in finding them!
Makers of Old Bagpipe Place Home
The bagpipe to the right in another probable set of George Glen bagpipes that I had the pleasure of restoring.  Many of the profiles and details line up however not makers stamp could be found. 
The Bagpipe Place Museum