In a large bowl or plastic container, mix together the olive oil, mustard, maple syrup, rosemary, garlic, salt and pepper until well blended. Add the pork cubes and turn in the mixture to coat; refrigerate for at least 2 hours, or preferably overnight.
Soak 8 8 to 12-inch wooden skewers in water to cover for at least 30 minutes. Core and seed the bell pepper, and cut it into 1-inch pieces.
Preheat the broiler or grill. Skewer the pork cubes and bell peppers, dividing them evenly between the skewers. Discard the remaining marinade.
Broil or grill for 6 to 8 minutes total, turning as they brown, until they are just cooked throughout.