The creation of a custom chin implant is done by hand off of a 3-D model created from the patient's CT scan. Having done this on a regular basis, the costs associated with entire process are well known. Short of the cost of getting a 3-D CT scan in your geographic area (usually less than $500), complete surgical costs would be right around $8500 to $9000 which includes implant fabrication and sterilization, surgeon's fees, operating and anesthesia fees.
To customize a chin implant, you will need a 3D CT scan of the mandible and face. This is then reconstructed on a 3D CAD machine which, if the company ha will be able to make you your custome chin. Cost I quess $ 50-100K