I think going with that to graphics card vendors first makes more sense. Case vendors won't get onboard first if we don't convince card vendors because what does "convincing" actually mean here - it means asking to manufacture a product within spec. Risking manufacturing cases in the spec before the cards are there is a no-go.
For graphic card vendors it's a different story - there will be tons of cases supporting smaller cards and convincing them to go for this kind of badge/rating/award for few models they would have makes more sense and this is what we should be actually aiming for.
There won't be new cases restricted to such spec if there are no card vendors onboard. Unless your point is to get in touch with case makers to sign and back up the initiative without manufacturing cases to such restrictions, but then it can backfire if we end up with just few of them backing us while most of the case vendors will ignore us and this will actually show the card vendors that big case makers don't care.
I would use community polls to decide what should be in the spec and what not, but once that set and we decide and make a document with specification and explanation I would rather go for number of signatures than a poll. With poll you will get a lot of people that are not invested in the topic enough to understand that making such standard doesn't mean we're going to take away their big and beefy cards altogether and they will just vote against it because of that.
Also a poll with just numbers doesn't prove the actual numbers of people taking part in it. And requiring email verification isn't something that can stop you from generating a temporary email accounts just to vote.
What I think could make a lot of sense would be to make a signature page collecting nicknames + country + list of significant SFF cases those signers owned. We could have a threads where people on the forums/subreddit would write a comment and we would combine that into a page/section of signatures in the document, or we could just link to those threads and threads could have limit of one comment per user and there could be a requirement of the account being at least a year old with at least amount of posts, and the document would just show the numbers at the time of revising/updating it.
There are people that tend to get almost every new good and/or interesting case and they end up having multiple of them as a hobby and there are people buying and selling those cases once a new one comes - those are the people with actual experience with multiple SFF cases and trying to match the hardware to them should be the people that matter in signing such spec, not the anonymous random naysayers that will flood the polls if we get some youtubers on board to spread the word.
