You don't need any special parts to attach a drill to the Model A - but you do need one with enough power to run at a low speed. I recommend the Model A because it is the only one that can use the gear drive option. Even though it is fairly expensive at $50, you will never have any issues where one roller stops and you need to tweak it to get it to start up again. I'm not sure whether that is common with other mills or not, but it has never happened to me with the gear drive.
Mine doesn't have any mods to speak of so it isn't worth a photo, but if you look at the large hopper adapter on this page:http://schmidling.com/maltmill.htm
Mine looks just like that. The only thing I would do a little differently would be to try to rig up some sort of conical bottom in the bucket. The instructions have you put a small hole in the bucket to slow down the grain as it goes into the hopper. The last pound or so of grain needs to be pushed toward the hole, so a conical bottom would be a little more convenient.