I would actually be more in favor of Canon doing a 'Kickstarter' type thing for a few of their dev's, with matching percentages. So we as a user base could have 'asks', the dev's could put a price on it, Canon could say 'we'll cover $X' and as a group we could buy in. Access would have to be limited somehow (firmware expansion is registered to a SN, with a build on demand per SN registered).
This would allow for things to be under NDA, supported in the event you send in for service, popular features could be worked back into the mainline, and fringe features done at a cost. It would also allow for an 'enhanced' firmware that could be sold state-side, over 30min video for example, while not incurring the VAT.
For example, I would pay for the ability to use my iPad as a full on tethered control pad. The ability to pick your exposure bracketing, or use the iPad for AF control, pure bliss. Most people would want this, but enough to pay for the development? I think so