arena-type idea?

I've been thinking about a good expansion idea, where the entire expansion is one giant arena, where you start at the bottom and work your way up, leveling up in traditional rpg style, and each fight is harder and harder, but you visit shops between each one and get gold for each fight, eventually you will reach the top and fight the highest level monster in the game, but not after hours of fighting single bosses and hordes of weaker enemies (assuming the editor doesn't crash horribly) it is a simple streamline design that could work very well I think. if I make it, I'd release it for free, but it's at someone else's liberty if they beat me to it, just be sure to credit the idea!