Don is the in-house mandolin expert at Ohio's Stewart MacDonald Guitar Shop Supply. In the mid-1980s he designed, and Stewart MacDonald sold, the StewMac 5-string electric mandolin (above left), which had the distinction of being the first production instrument to incorporate the Parsons/White string bender made famous by legendary guitarist Clarence White. (This dandy little gizmo allowed the player to bend the pitch of the A string by yanking on the strap, creating some cool steel guitar effects.)
In addition to the production line of instruments, Stewart MacDonald also offered a kit based on this design, which luthiers could buy and finish on their own. It might well have been the first electric mandolin kit. The blond instrument pictured above right was undoubtedly made from one of those kits. Notice that it lacks the string bender.
StewMacs are the first electric mandolins I was aware of, but they have been unavailable for several years. Don is currently building Red Diamond acoustic mandolins, and says he has no plans to reintroduce the StewMac. All told, he reportedly built about 45 of these instruments and sold a few hundred kits.