I've just found your website after doing a google search on "Broken Tailbones" and from what I've seen it looks pretty useful.
I myself have suffered recently from a "broken" tailbone after I slipped whilst carrying an arm load of firewood. That was a couple of months ago and I've been suffering through the pain as there really isn't much that can be done about it.
As a result of the accident I also did some joint damage where my tailbone joins into the pelvis which started causing me serious back pain resulting in me seeing a chiropractor.
After x-rays to find out just how much damage I had done the result came back that the end bone had been displaced by half its length (about 5 mm).
I've seen a couple of comments you made regarding tailbones and believe what you've said is not entirely true. My Chiropractor told me this: Peoples tailbone configurations differ, in some the bones are essentially all fused and have no cartilage between them so it is possible to have a "broken" tailbone. In other cases where the bones are separated by cartilage then what really happens is more of a "dislocation" which causes the same pain and discomfort. Because of the way they are joined by the cartilage however it is still technically a "break".
In some cases if the injury does not heal and continues to case pain then it can be operated on and the offending fragment of bone removed. In women this is more critical as the position the bone ends up in can cause problems/pain during childbirth if it is not corrected.
Note from Jon Miles - See The normal coccyx and Unstable or dislocating coccyx