It would be difficult to have a user-based convention.
and all cosplay as our icons
This quote makes me believe you meant for the users to all meet up somewhere.
Actually, even for the US, it would be difficult to get a userbase together who is often still reliant on their parents’ income or aren’t in a position to go tripping so easily. If you must put together one, I might suggest holding one where most of the users are…in the Midwest
You’d probably be more easily able to get people to make long roadtrips, and it would certainly be easier to find venue/parking/accomodations/reasonable prices up there than in NY.
What might be a consideration is to have webinars put together by staff, top-tier editors and entry moderators on KYM, and various other experts on Web culture. You wouldn’t have meet ups, merchandising, or the ability to turn a profit (unless you charged something for access to the webinars, which, per the Internet, might be able to bypassed anyway) in that format, but you could have a few days where you have a lot of people giving “live” information in lieu of panels, and no one has to take more time out of their day than they have to being at a convention.
That has its own problems, and I wouldn’t propose it anytime soon, but if there was enough interest and it was “marketed” well-enough, it might be something that at least makes sense.