...remove Mario, minigames, add RPG elements like random battles, job classes and levelling up, put it in a Risk-like world map where you invest on towns and collect their taxes, add backstabbing and put it together?
You get Dokapon Kingdom.
http://ps2.ign.com/articles/939/939140p1.html
You HAVE to play this game at least once. I'm serious. It's like $19.99 new for the Wii, $29.99 for PS2 (for some odd reason lol).
Basically, it's a Mario Party-like board. A spinner rolls between 0 and 6, you move that many spots (in ANY direction, allowing you to go back if you need, or take alternate routes). You could land on a get-item or get-magic spot, and a roulette will determine what you get. There are free, empty spots, too. Instead of getting 3 coins on the free spots (lolMario Party), however, you get a random battle or event! Battles are, well, BATTLES! Each day (turn) the battle starts, the first player is decided and that player attacks first. The other player is the defender, and each have their own selections from the D-Pad (or face buttons on PS2). If the attacker chooses Attack, the defender better have chosen Defend. If the attacker chose Strike, a Counter will evade the strike and hit back for twice the damage. If the attacker decides on Magic, a Magical Defensive spell will work to reduce that damage. The attacker could use their class's special ability, too. These can increase attack, defense, magic, or do something else. The defender has a chance to Give Up, too. Like any RPG, win and get Experience Points toward leveling up, money and sometimes even items. After the first player attacks, it's the second player's turn. If both are still alive, you will live to fight another day... literally! As in, it will say "To be continued" and you will continue on the next turn. Losing a battle means you're returned to the previous castle or temple you visited and are forced to skip anywhere from 1 to 3 turns. Giving up, you only lose 1 turn. Also if you give up, the opponent can't take over one of your towns, so this is important.
When leveling up, if you have not mastered your job, you get 2 extra points to distribute as you wish in addition to your job-determined leveling up. When mastered, you get 3. Getting a higher level on your job means a pay raise (honestly), and you get paid every week on Saturdays after everyone's taken their turn.
Events can range from an old guy asking for money (then either disappearing or giving you something in return), to a random girl wanting to play Rock Paper Scissors for all your money, or a bandit that, for a fee, will attempt to steal something from another player. There's even a random event where you're abducted by aliens and apparently experimented on (which could either permanently decrease or increase your base stats). And one of the most awesome ones, you can find a robot that would like to help you get rid of other carbon-based life forms so for a fee you can hire it to hunt a player down!
Yes, backstabbing is the name of the game, and being nice can only get you so far. After doing your shopping at a store, if you feel like you didn't get your money's worth (or are 100% short on cash lol), you can attack the store owner! And you two then engage in a serious battle of... Rock Paper Scissors lol Win, and you will either get INCREDIBLE ITEMS, or their most expensive item! Lose, and you're a wanted criminal with a bounty on your head (which any player that defeats you gets to keep!), and you will not be able to save towns, enter towns, castles, shops or temples until you're defeated or the week is up!
Beat one of your friends and choose your destiny: rob them of something (money, items, magic, even control of a town), give them your status ailments, or pull a prank on them! Change their hairstyle, draw on their faces or even change their name. To ANYTHING. Sure, you can also forgive them (and this is helpful in forming alliances, a player can give up and the other can forgive them and NO HARM will come from it). But where's the fun in that!?
You can defeat monsters in front of towns to claim ownership, which means you govern over them. Land on them and you can stay for free and heal, collect taxes or invest in the town (which raises its base value so it increases their tax income and raises your net worth, I'm not joking, seriously). However, via spells or random events another monster might appear to attack your town. The town no longer belongs to you! If another player gets to kill the monster, they take the town away from you!
You can go to another player's town (and stay for a fee), and leave peacefully... or attack with your deadly Rock Paper Scissors prowess! Succeed and you get their taxes! Lose... and you're a wanted criminal for a week.
By the way, a day consists of every player taking their turn once. So... You're a wanted criminal for 28 turns in a four player game. Good luck.
Between weeks, each player's total net worth is calculated and a stock-market like line diagram shows how each player's value has increased or decreased in recent weeks.
Oh, and stores are closed on Sundays lol, and they also have sales on a random day of the week.
There's a lot of other awesome crap you need to see for yourself. Here's a 12-minute clip of the game.