Just switch everything over to conventional 12v stuff. For the LS swaps I've done, I always use a Walbro fuel pump mounted to the frame rail, with a Corvette style fuel pressure regulator. This sets the fuel pressure to the correct PSI, and also eliminates the need for a return line at the fuel rail. It has it's own return built in, so you're only plumbing a return line about 3' long, instead of running it the entire length of the vehicle.You should offer these to people who want to do it. I would prob go LS if my 6.5 was not salvageable. I guess you would just convert everything to 12v then? Intake pump, swap out the lights and switches? Am I missing anytbing?
As for the rest of the driveline surviving an LS, it should survive no problem. I would imagine if you beat the bag out of it, it'll break something, but the same would happen with a 6.2/6.5.