Prick the potato skins all over. Bake the potatoes in aluminum foil wrappers until tender, about 45 minutes.
Meanwhile, cook the bacon in a small saute pan over medium heat until crispy, 8 to 10 minutes. Remove the bacon from the pan, leaving the fat behind. Add the panko and garlic and toast until browned, 2 to 4 minutes. Combine with the bacon, draining any excess fat. Season with salt and pepper.
Remove the potatoes from the foil while warm, and cut down the centers lengthwise without cutting all the way through; scoop the centers into a bowl.
Mash the potatoes with the cream, butter and truffle. Season with salt and pepper.
Preheat the broiler. Place the potato mixture back into the skins and top with the fontina cheese. Broil until the cheese is melted and bubbling, about 4 minutes.
Garnish with the breadcrumb mixture, chives and more shaved truffle and serve.