I'd like a 6-8mm Nagler Zoom too, or better still a 6-12mm would be fantastic! Perhaps Al nagler will make one some day.
You will see there is no such thing as a 6-8mm Nagler Zoom as they only come in 3-6mm and 2-4mm although I noticed Tele Vue now refer to them as 6-3mm and 4-2mm.
http://www.televue.com/engine/TV3b_p...9#.Ux_qp7lWG9I
Tele Vue used to sell an 8-24mm zoom but it was not a 'Nagler' zoom.