Disclaimer: I would love a Tesla model S, but even with the mentioned loans could not possibly justify buying one over saving up for my children's education.
It is ridiculous to try to prop up the success of a company by government backed loans. If electric cars will succeed, let them do so on their own. I personally hope they do, but think that X-Prize style awards for better batteries/chargers is the best way to do that.
However, I think student loans are one of the worst things our government has ever backed(worse than the Tesla loans). By providing them we encourage an already existing problem of people getting degrees when they should be learning a trade instead, and mounting up debt that will take them twice as long to pay back. Scholarships and Pell Grants already exist as an excellent tool for providing assistance to the most needy, and the most deserving. Furthermore, working your way through college is not only doable, but builds character while reducing the amount of trouble students get in to. For those instances where there is a real need for a loan, such as medical school, the government isn't really needed. In addition to grants, the government already provides assistance for those who have served (GI Bill) and those who will promise to serve (ROTC Scholarships). There is some of that in the private sector (hospitals, chick-fil-a, etc.), but I'm all for the government encouraging more of it.
Finally, if we did a better job at the grade school level we wouldn't be trying to squeeze unprepared students into college curriculum while they are building up tremendous debt attending institutions they won't be able to graduate from. The real problem with government assisted student loans (and most risky/payday loans in the private sector, but that is a separate gripe) is that they are an attack on those the current system has already failed while giving an empty promise of an easy out.