Is there such thing as a Mario Kart type game, but with Smash Bros. characters? That would be incredible.
I want a Dynasty Warriors game with Super Sentai/Power Rangers. The Japanese release would us the original Super Sentai, probably being called something like "Sentai Warriors" while English localizations would turn it into Power Rangers, which would be called something along the lines of "Ranger Warriors".
A Final Fantasy x Monster Hunter crossover would be kinda cool, not really sure how it would work out tho. XD
I've heard that Final Fantasy Explorers on the 3DS is basically just Monster Hunter with the monsters and character classes taken from Final Fantasy. So in a way, this crossover already exists. Also, both Final Fantasy and Monster Hunter have both had collab events in Puzzle and Dragons.
I'm curious about what exactly you have in mind for this one? :'-) On the note of Harvest Moon, a crossover with Pokémon would be quite interesting... Growing berries on the farm while raising Pokémon both for produce and to sell to trainers? There're plenty of gems and minerals to cover the mining aspects too (I would also very much like to marry certain characters in the game but let's not venture there haha).