Heat oven to 350F.
Combine ham, egg yolks and mustard in food processor container fitted with steel blad. Process until blended. With machine running, add whole eggs, one at a time. Add milk, cream, port, tomato paste and pepper; process until completely blended. Taste and add salt if necessary.
Ladle mixture, dividing evenly, into 8 lightly buttered 8-ounce custard cups. Place cups in roasting pan lined with double thickness of newspaper. Ad hot water to pan to come halfway up sides of cups. Cover pan with aluminum foil. Bake in lower third of oven until custards are just set, 35 to 40 minutes. (Be careful not to overbake.) Remove custard cups from pan; cool completely on wire racks.
Blanch peaches in boiling water for 1 minute. Plunge into ice water to stop cooking. Peel, cut into quarters, discarding pits. Cut the peaches into thin slices.
Unmold mousses onto individual serving plates. Garnish with peaches, watermelon rind, and almonds.