I'd be down but having a 72-48 hour window would probably be better for everybody's sanity and sleep schedule.
Trust me 24 hours straight of mapping sucks balls.
My only request for this would be everyone needs to start from a blank vmf and limited prefab usage. Stuff like drexen's timer, a simple cp setup, or a brush font would be fine imo, but if somebody just has an extra jump laying around it shouldn't be allowed.
For difficulty I would try to stick to T4 max just because those are easy to test.
I like the idea of having judges, maybe have a couple that have never opened hammer but are still good jumpers, and a couple experienced mappers.
wasn't hexahedron done in 24h?
30 hours over 3 days