HEAT oven to 350 degrees F. Cut slice from top of bread loaf; remove center of loaf, leaving 1-inch-thick shell. Cut removed bread into bite-size pieces; cover and set aside for later use. Place bread shell on baking sheet. Bake 8 to 10 min. or until lightly toasted. Cool slightly.
MIX VELVEETA, tomatoes and onions in large microwaveable bowl. Microwave on HIGH 5 min. or until VELVEETA is completely melted, stirring after 3 min. Stir-in ham and pineapple. Pour into bread shell.
SERVE with reserved bread pieces and assorted fresh vegetable dippers.