The two are so very different, especially with unibody construction, that conversion would not likely be cost-effective. Also, I would be concerned that your modified vehicles would not meet safety standards, leaving you open to fines and lawsuits. Even if you think you're doing a good thing, if someone gets hurt (which they undoubtedly will), some ambulance chaser will sue your pants off, insisting that the victim obtained this modified car from you in good faith, assuming that it was safe to operate or park and leave their children strapped in their car seats. You need to Google "EV bus fires".