I was thinking along the same lines... Since the Beaulieu Superdrive was never properly adapted to the beautiful Nizo's, I opened up a 60m cartridge to see how it worked and whether it could be refilled (Velvia, K25, negative...).
Up to now I can say that it's not a job I would like to do in a darkroom WITHOUT night vision goggles :blink: A real can of worms...
Hopefully the pictures are of some help. To open up, you have to cut with a sharp Stanley knife all along the seam and then gently prise it open.
Regards,
Alex