New game mode concept

can there be a game mode where games are intended to last ATLEAST 40 minutes, you can level past 18, and basically its a late game champion/player heaven? Or perhaps you start level 18 and items are free?

I really like to play in the late game and would like a game mode where i can basically just play in the late game. and try whatever weird builds i like to see how they would work in the end game. one way to possibly extend the game in these modes would be to double or triple structure hp WITHOUT ADJUSTING ANY DAMAGE.

Just a secondary game mode concept i would love to play.