The great thing about an education is, besides the degree, the team-based environment encouraging you to put in those 40 hours, critical feedback and fuel for your design cycles during presentation sessions and the conversations you have with experts and your target users. If you think you can fill that in with a private study I think it can work as well. For one, more and more schools such as MIT have started this year to publish their course materials online, for free under the OpenCourseWare Consortium. The MIT classes alone will get you a long way, they include everything from materials science, manufacturing knowledge, design projects, furniture, new product development and research processes, CAD (Solidworks), rapid prototyping, sculpture, toy design and sustainability. Then there are the classes on electronic textiles by Leah Buechley, Neri Oxman for biomimetics and Roz Picard for affective computing.