Got the 'Slade back from the shop. While they were waiting for another replacement OE headlight ballast to come in, they were moving the truck and the driver's side (which had previously always been fine) decided it was going to quit too. Same deal, bad ballast. Obviously there was something going on with the system, and I wasn't going to put out $1300 for 2 OE ballasts only to have them fried again; so the shop sourced an aftermarket HID kit that would work with the existing D1R bulbs and wired it in, using power from the existing harness as a switch and getting main power to the ballasts from a direct 12V source (through a relay). So far it's working great - hopefully it holds out. Aftermarket kit + labour ended up costing me $350, miles better than the $600/ea for the OE ballasts alone.