My guess is if your doing a mod, you'll be able to still choose a gigantic map size. And build it all by hand.
But otherwise, I'm guessing they just gave us a hand built map for a general size large, but it's not the full parameters. Just a general size for the testing due to it being easier to just go with a generic side.
As far as you getting that 64 bit support that you've been asking for, these last few months.. my guess.. not in the first 60 days. As there will be a lot more coming out on their end. (Now that's just a guesstimate. And I accept that, it may be wrong. But there was a general reluctance for rushing that 64 bit version out so quickly, as alluded in past conversations, and comments by Brad.)