Phase One and Rolleiflex offered a digital bundle package long ago with a P20 fit to the 6008AF. Sinar also had and eMotion kit with the 6008AF. Rollei Metric which was bought by Trimble was fitting phase p20, p25+ and P45+ backs to the 6008 mostly for aerial work, but anyone could get them to make an adapter. The price was pretty high ($3000 approx.) so not sure how many were made but one did occasionally see them. There was a forum member here that made his own, and I know that a technician in Los Angeles, Austin Calhoon, is considering undertaking the work to make his own 6000 back adapters for resale.