In a saucepan large enough to hold all the pears snugly, combine the water, sugar, ginger root, and vanilla bean. Stir over low heat until the sugar has dissolved and then increase the heat so that the liquid is simmering. Add the pears and poach them for 15 to 20 minutes, turning occasionally so that they are evenly covered by the syrup. The pears should be tender enough so that they can be easily pierced with a toothpick, and the cooking time will depend on their ripeness. Let cool, and refrigerate.
In a food processor, process the almonds and the sugar with an electric mixer until smooth and flatly ground. Do not overprocess.
In a large mixing bowl, cream the butter with an electric mixer until smooth and fluffy. Sift the almond powder and the flour over the top and combine to beat until smooth and fluffy. Beat in the eggs, one at a time, mixing the first one in thoroughly before adding the second. Add the rum and mix in thoroughly.
Preheat the oven to 400 degrees and lightly oil a large baking sheet. Halve the poached pears and scoop out the cores. Slice each half pear thinly lengthwise and set aside, keeping together in their original shape. Unroll the phyllo and cut it into 4-inch wide stacks. Separate the leaves of pastry and lay one single strip on the counter. Brush it with melted butter, and continue until you have a stack of 6 strips, buttering each one. Repeat until you have 6 stacks of buttered phyllo strips. Using a spatula, spread a layer of almond cream 1/4-inch thick on the top layer of each phyllo stack. Slightly fan out a pear half on one end of each stack and roll the stack over about 1 1/2 times to form a flat strudel package. Brush the outside of the strudel with butter, and repeat with the remaining 5 pear halves and phyllo stacks. Transfer the strudels to the baking sheet. (at this point the strudels could be refrigerated for up to 12 hours before cooking)
Bake the strudels for 10 to 15 minutes, or until golden and crispy. Cut them in half and place with cut sides up in the center of each of 6 dessert plates. Place a scoop of chocolate sorbet on the side and serve it at once