The best dummy I've had was one I made. My students used it as a throwing dummy or generally beat-up dummy and basically destroyed it. Ironically, after destroying it, a number of them realized its utility and complained when I had to get rid of it (I essentially gave it "joints" and the constant slamming destroyed those joints, and also, tears opened up which allowed bugs to infest it).
Part of me would say look up some of the websites and videos about making a grappling dummy and incorporate those ideas and your needs into your own version that you make, because if I could make one, anyone can.
However, not wanting to go throw all that labor again, I ordered a fairly cheap one that has worked out pretty well; it has a target shape on its "head," but so do a lot of them, so I'm not sure exactly what brand it is. I would just look at Youtube videos of people using the various models so you can get a sense of what you're buying. Personally, I'd go with one of the cheaper 30-some dollar unfilled dummies first, just to get a sense of what you might want or need. And also because they might end up working out just fine. If they don't then, you'll have a better sense of what was missing and what you want and be able to seek that out from the more expensive ones or incorporate that into one you build more effectively. If you do end up building one, an unfilled 30-dollar dummy could make a great starting base for it anyways.