A Da Yi brand panoramic 6x17 cm roll film back for 4x5 Graflok back field and view cameras is available via Ebay:
https://www.ebay.com/itm/203714427140By positioning the film plane an inch or so behind where the 4x5 ground glass is normally located, the image size increases sufficiently to cover the 6x17cm area. A separate ground glass and bellows viewing hood permits framing and focusing. $450. Ships only within the USA.
