1977. The /60 was an expensive "middle-class" machine, intended as the successor of the /40. It should have been introduced after the /70, but was delayed at least 12-18 months due design and debugging problems. It had a writable control store (WCS) for custom instructions, and floating point instructions were implemented in the CPU microcode. It also had 18-bit memory management. With the FPP option it had the best floating point performance among the -11's.
As for packaging, it came in the "low boy/high boy" cabinets, the one pictured to the left is the "high" one. The storage devices could be placed in the upper region, the card cage itself was in the lower half.
Trivia: The 11/60 was the fastest PDP-8 ever built: Ritchie Larry re-microcoded one machine, the computer was used as a software development system.