I don't believe a Kickstarter would be appropriate here. There is no tiered payoff incentive available that would entice people to make various donations. What would be given away is very specific to those who own or will own a $3500 camera body, so you are narrowing the number of people this Kickstarter would apply to. I know this could be argued against regarding any endeavor where specialized equipment is required, such as sliders, steadicams, iPhone products, etc., but each of those fund raisers give different tiered products or credits for rewards - in this situation the contributor receives ML which is already free, and that, is that.
I have already made my donation towards the Mark III, I do not own one, nor do I plan on owning one, but I know that the continuing development of ML on all Canon DSLR's benefits ALL of us!