I think if someone actually did that with legit methods, that [S-HIGHLIGHT]they could safely say they are the pokemon master[/S-HIGHLIGHT]. :O
I can't imagine all the hours of grinding...... >_<
But no, I've never heard of anyone doing that. Maybe in the first Gen when there were only 151, but not now.
I've been playing Pokemon for years, and I have never gotten one Pokemon to level 100 in my entire life.
With over 600 Pokemon now, I don't think I could ever think to try.
Anyway, I've attempted to achieve the daunting task. Unfortunately, I have lost 2 Sapphire cartridges, both with several Level 100 Pokemon on them. I do intend to achieve the goal one day; it's just going to take awhile... :\
It would take a long while, by time you finish leveling up all the pokemon in one Gen, they would be out with another one. :S