Yes you can, they have bolt in motor mount kits at 4x4parts.com. There are several V8 D21's out there, look around.
It is possible to put a V8 in anything. Although, it will require lots of fabrication and $$$$! You're not going to be able to just take a V8 and drop it right in.
yes
No, the Nissan GTR R35 is a V8.
The 1996 year model 7.3L Powerstroke Turbo Diesel V8 put out 295 horsepower.
Yes
The 2013 Nissan Titan has a V8 engine.
The 2012 Nissan Titan has a V8 engine.
The 2014 Nissan Armada has a V8 engine.
The 2014 Nissan Titan has a V8 engine.
The 2012 Nissan Armada has a V8 engine.
The 2009 Nissan Armada has a V8 engine.
The 2007 Nissan Armada has a V8 engine.