I got a fake surveillance gadget today for the front porch. It looks like one of those surveillance domes with the cameras inside of them that you see on the ceilings of department stores, only this one has a motion sensor inside and a little red light goes off when it's triggered. DH is going to run a wire from the gadget to the house so it looks more authentic. I'm still working on finding a "premises under video surveillance" sign or sticker for the front door, but I think the doorbell ringers will think twice once those deterrents are in place.
On behalf of Chief, Sarge, and my felines, thank you all again for your input.
My Boxer World family rocks!