Preheat BBQ to medium heat and lightly oil the grate.
Mix together the cream cheese, Parmesan cheese, garlic powder and Cheddar cheese in a bowl until the mixture is thoroughly blended.
Lay a jalapeno chilli onto a work surface and cut a lengthwise sliver from the side of the chilli, exposing the seeds and white membrane. With the handle of a teaspoon, scrape out the seeds and membrane, leaving the hollow chilli. Repeat for the rest of the chillies. Chop up the chilli slices then mix into the cheese stuffing. Stuff each chilli with cheese mixture then wrap each stuffed chilli in a half bacon slice. Secure with toothpicks.
Grill the poppers on a less-hot part of the BBQ until the chillies are hot and juicy and the bacon is browned, 30 to 40 minutes.