The very best of the best won't have time to do it. They have there own case load. Back to my point, pick one area of law, learn it well don't try to do the rest. Still don't know a damn thing about criminal law. Guess what, doesn't matter, because I don't take criminal cases.
New attorneys work like slaves almost everywhere, and they are lucky to get the chance.
Jobs are scarce everywhere. Of Counsel means different things to different people. Most likely, the way you describe it is that the client will remain under his firm. You do the work, he does the administrative. He'll bill the client and give you a cut.