This would be a lot of fun, and makes me more excited for Regionals! (Presuming that Florida is invited/my teammates want to register).
I personally think 20ish teams would be nice. Something that approximates the top two brackets of Nats. I don't think this would depress regional sites more than a 10ish team/one top bracket would.
Invitation-only would be tricky. What is the metric? The pre-season poll? Winter/IKEA ppb? But, on the other hand, a first-come first-serve approach could defeat the purpose of a super-site if a bunch of teams signed up before the likes of Stanford A, Illinois A, Chicago A, or Columbia A.
An idea that came to mind is: invites could be sent based on the pre-season poll, but then a team's invite expires if they do not get their packet in by the second packet submission date. After that date, teams not originally invited would be added based on a waitlist queue, if there is room.
My only concern is staff. I feel like a super-site would slightly increase the number of teams playing Regionals while simultaneously decreasing available staff, as some nationals contending teams would play at the super-site instead of staffing their regional site. With sites for both Fall and Winter asking for staff up until the day before the tournament, the slight reduction in staffers/increase in players could cause logistical issues for regional sites.
There are some possible counterarguments (that I can think of/that have been brought to my attention on Discord) to the above paragraph that would obviate any staffing worries:
- Teams playing the super-site wouldn't actually provide that much staff to regional sites
- The loss of staff is offset by the reduced turnout for Regionals as compared to the turnout for Fall and Winter
- Hold the super-site on a different date