That's not a problem and can easily be achieved by using CSS only.
You could output the menu as a unordered list (using the Menu(1) control as usual). By setting the ul and li elements to a fixed with and by using float you can create a "grid".
Example: li have float: left and width: 100px, ul has width: 300px. To make it look good, the li elements should also get a fixed height.