As Jango pointed out, the seed is displayed in F3, so there's no point in trying to be obscure. Although, I suppose I could make the seed something like "YouCheater"
I did just re-create the world on my single player install. I gotta say, the place is very lonely without all the structures. The hill where the commune resides just looks wrong...
Don't worry, I won't be using any mapping tools to find everything. Not that it matters since we will be going to a new world. But I think that takes all the fun out of the game anyway.