Yeah, this probably should have started in Houserules... I think my original though was how to use existing rules (and rules in the DMG) to support it, but it does quickly move into a houserules category.
And I agree that he is fixating too much on this tactic. I think he feels that this is a "fundamental" ability that 4E dropped the ball in not allowing. He doesn't want to make into a power, because he feels that's the equivalent of having to take a feat or power in order to bull rush or charge.
The character concept he wants is basically a rehash of a character he played in a D20 game previously.
Trust me, it's frustrating for me too, feeling forced to defend what I feel is an arbitrary and unimportant "feature" that was "omitted". He seems to focus on the things that are no longer possible, without really seeing what new things have become possible. He has trouble seeing that it's different, but it's not really a net loss.
I think he seems to resent changes and omissions in 4.0 that were "unnecessary" and doesn't seem to see how that many of these "unnecessary" changes really were necessary to fit in with the overall design philosophy changes.
Everytime he finds out some random 3E combat maneuvers isn't standard in 4E, he has a negative reaction. He also resents that monsters in 4E don't "follow the same rules" as PCs. Things that I truly see as ranging from not a real loss, to sometimes a positive thing. I was so sick of shtick builds in 3.0 that typically were about forcing enemies to provoke AoO's using some gimmick and punishing them for it.