9 String Guitars
Getting a 9 string guitar is a great way to show your bass player that he really is expendable. ;)
Maybe the low F# on the 8-string isn't quite bone-crushing enough for you and the low C# of a 9-string can fill that void for you. Or maybe the F# is low enough but you want an extra high string. Options are good, right?
Nine strings aren't exactly mainstream at this time, but I can see where those who keep both hands on the fretboard can really take advantage of the extra range.