I don't know if this topic is still viable but recently I followed your related posts in the forum and it is very interesting to me because your questions stem from human science, not design. Please see my response to your posting titled "Social scientists in design research?".
As far as your search for an online course in design methods,I would caution you that academic or instructional courses outside of design practice can be misleading, if not irrelevant. I think it is worth posting in this forum, for you and especially for those beginning their careers, some social reality of industrial design as an occupation. First industrial design, as differentiated from product design, is a profession, in that industrial designers are socially formatted and selected to advance into the occupation based on personality traits that are ameneable to interacting with decision makers in buisness that industrial design provides service to. Secondly, the service industrial design provides to business is a part of the collective activity that comprise a business world. It is the copperative activity of this 'world' that industrial designers participate in, but rarely finally determine product success. These two factors comprise the activity, and consequently the role of the industrial designer. The role of the industrial designer includes a methodology and may be of academic and intellectual interest, but there is of little consequence in business practice. A good example is the case where a designer uses a methodology to develop a successful sunglass design in the United States. This design is certain to fail because of structure, not design, in the prevailing U.S. fashion eyewear industry. In the aforementioned case, design methodology is of no consequence to product sucesss. Therefore, it is an important critical view of design methodology to regard it as specious, without a countervailing process of evaluation. I can't imagine any course you will find, outside of optimization, that will have a countervailing process of evaluation.
That being said, I think you would be better served by looking at the feild of business, for example of how industrial design is a product development resource, in particular, case studies involving innovations within a brand or market sector. I think you might be able to see that product development is a procedure and each of the product development stages deploys activity of different abilities. Advertising and its 3D analog- industrial design, both provide a product development service to business through a holistic process,. Perhaps to better understand the potential and perils of holistic design it might be helpful for you to compare the similarity of the holistic process in industrial design to that of holism of diagnosis(psychotherapy) in your chosen field of psychology.
So in closing, what I state above can be studied(if I understand your inquiry aims to-date in this forum) through the social research methods of case study, endomethodology, or consumer behavior. I think business case studies, rather than design research courses, would show how industrial design is integral in the activity of product development. Also it will help you undersatnd how products of collective activity bears the marks of the action of those who produce it (Becker).