Has the building technique of Technic pins in a brick cylinder been used in an official set?
I'm not aware of this being used in any official sets, but I'm happy to be proven wrong. I can say that LEGO considers this to be an "illegal" connection. The Technic pins need room to spring back out and be "in click", or they can be permanently damaged by prolonged assembly. LEGO would not allow this connection to be used in a current set.

A Technic pin not "in click" was used back in 2002 in the Audi TT and led to part damage as well as this sort of connection being banned from sets: