I do know a microwave crumble recipe, although the topping isn't quite the standard crumble.
Put your fruit mixture in the bowl (won't insult you with a recipe for that) and for the topping (assuming you're feeding around 6 people), you need
5oz Jumbo Oats
2oz pecans or walnuts, chopped
4tbps sugar or sugar substitute
1/2 tsp vanilla extract
3tbsp butter or margarine (I have sometimes substituted walnut oil)
1tsp cinnamon
Mix together, put on top of the fruit, microwave for 6 to 8 minutes (depending on hardness of fruit). Leave to cool a little before serving.