No, true custom clips are not free. But if you find a producer which makes stuff that is close to what you want you may be able to interest him in your ideas. I found producers can be quite open for this. Just don't send them pages of details and don't expect they follow your suggestion to the letter. If that's want you want - you pay. If you agree that the producer can sell you clip, and if he wants to, you should be able to get a better price.
BTW I have tried some custom clips and apart from getting a clip to my taste, I got a kick out of knowing that the model I picked would not have found herself in just that position, having exactly that done to her, if it wasn't because I had ordered the clip 🙂
Good luck!