To the original poster, if you want to hunt rhino and it is legal where you plan to do so. More power to you. The governments that control the populations of rhino in their country determine if there are enough to allow limited hunting or not. I personally will not critize anyone who chooses to hunt legally. It is their right to do so.
Let just say, I value and protect my rights, and don't like it when other people try and step on them because they don't like how I practice those rights.
I will say that there are options that are equally challenging to and in somes peoples views better than hunting to kill a rhino in Africa. First would be the tranquilize and study / tagging method mentioned earlier. Personally that is the choice I would make. Costs less, lets the animal live, you can get a replicated trophy, and science gets info. Sounds like a win / win to me.
Another option would be to research and look at a hunt in the US. A big part of the recovery of endangered african game is that US ranches have agreements where they breed and raise various endangered african game on their lands and a certain percentage are returned to Africa to be released. These game ranches offer hunts for a limited number of rhino every year. These animals are not endangered, and many of them roam on huge ranches that can be considered fair chase due to the size of the property.
In my state we get to shoot one deer and one elk a year. Is the guy in Arkansa, or Alabama who can shoot 7 to 100 deer a year unethical. NOPE! His states game laws say you can shoot that many. What about hunting wood chuck on the east coast versus Idaho wolves? Not a bit of difference in my book. Each State says theres enough to hunt. Each State says its legal.
Lots of people are wound up about hunting the wolves in Idaho. Frankly it is none of their business. Unless of course they live in Idaho. Idaho Citizens can vote and impact the states decisions thru their vote, attend meetings, voice their opinions, etc.... That is our process and that is how it is meant to work.
So I say go for it. Look at all you options, practice hard with a heavy bow. Put together some heavy UEFOC arrows and shoot for the boiler room. And for your own sake, dont hit it in the shoulder blade! A rhino will stomp you into the dirt, making a small reddish mud puddle.