Dear Arye,
You can achieve this with DS8A10 Model A00 now.
Be aware that with z16, there is no "reserve 16U space" feature as we had before with z14 and z15, so the z16 should be rack-mount, too (as with Model AGZ).
For co-racking of DS8A10 Model A00 with TS7780, there are rack mount installation RPQs available for the VTL, but currently with restrictions on future expansions.
Regards,
Ilja