photo: Scott Lyons
Your basic solidbody 8-string electric F5-shaped mandolin with an extended fretboard and a birdseye maple top. That might be a Seymour Duncan pickup—it does appear to be spaced for just this kind of instrument. Judging from the workmanship I'd say Miller—whoever he or she may be—is an experienced mandolin builder. If you've got more information I'm dying to hear it.