I have a very weak side profile. I don't simply want a large chin but rather a nice jaw line as well. (photos)

You are right, a chin implant alone will not give you what you want. However, placing mandibular implants is more involved and a minority of plastic surgeons do this procedure, e.g., Dr. Oscar Ramirez in Baltimore. You might have better luck if you look for one of the university-based craniofacial surgeons.  These are individuals who sometimes have DDS, MD and oral surgery backgrounds.

Without an exam your question cannot be answered. However, your photos are helpful and you are probably a good candidate for a Chin Augmentation. You will need to see an Oral/Maxillofacial surgeon to see if othognathic surgery, genioplasty or using an implant is best for your specific case. It should be noted that patients with severely weak jaws or abnormally functioning jaws may be better treated with other facial surgery (orthognathic surgery), although a chin augmentation may be an option at a later time. These patients should seek the advice of a plastic surgeon to determine which course is right for them. Here is some information to help you make this decision: Candidates for Chin Augmentation - Patients whose chin profiles are weak but have normally functioning jaws are candidates for Chin Augmentation. Many of these candidates have used injectable fillers in the past to strengthen the protrusion of their chins, but are looking for a permanent solution. If you are one of these patients, then you are a likely candidate for chin augmentation

In general, facial profile can be improved with the use of a chin implant and neck liposuction. This combination of procedures tends to produce a refined and elongated jawline 

In reviewing your photos, I think that you would benefit from chin augmentation (chin implant or genioplasty) and simultaneous submental liposuction. Kybella is another option to remove the submental fat. The idea is to increase the projection of your chin and give you a well defined jawline by performing liposuction. These 2 procedures work well together.

There is no doubt that you will benefit from chin augmentation/shaping with implant. This can be achieved with selection of appropriate implant that will address both size and shape of your chin. Implants come in an array of shapes and sizes and they should be available for demonstration in the office of the surgeon who performs this type of surgery.You should seek a consultation with a board certified plastic surgeon with good reputation in facial implants and discuss your options. Good luck.