Preheat oven to 350 degrees. In a large bowl, cream together the butter and 1 1/2 Cups sugar until smooth. Mix in eggs. Add the flour, cream of tartar, baking soda and salt; stir into the creamed mixture until just blended. Press dough into an ungreased half sheet pan. Bake in preheated oven for 13-16 minutes, or until lightly browned. Cool.
In a bowl, beat the cream cheese until smooth. Add the granulated and powdered sugar, vanilla, lemon juice, and lemon zest. Spread on the cooled pizza crust leaving an edge around the outside.
For the glaze: Combine the limeade, cornstarch, lime juice, and sugar in a small saucepan, whisk and cook over medium heat until clear and thick, about 2 minutes. Let cool. With a pasty brush, glaze the entire pizza. You will not use all of the glaze. Cut fruit and dry off excess juice on paper towels. Arrange fruit on top of the pizza. You can add glaze to the top of the fruit, if desired. Cover lightly with plastic wrap and chill until serving.
Recipe adapted from http://allrecipes.com/recipe/12604/fruit-pizza-i/ and http://www.melskitchencafe.com/fruit-pizza/ and http://www.foodnetwork.com/recipes/paula-deen/fresh-fruit-tart-recipe.html