I fly the 777 and have not found anything like a cockpit companion. A little odd when you consider the aircraft has been around quite a while now.
A chap who goes under the name of
Old Smokey on these forums, 777 driver based in Singapore and extremely knowledgeable about aviation technical subjects might be worth asking. See
http://www.pprune.org/forums/member.php?u=90911 and send him an e-mail or Personal Message.