I can't agree. While I'm still pretty sure that larger than "huge" maps will be a 5 minute mod (and limited rather by the hardware demand), you should try 1upt first.
I firmly believe that a certain map size destroys the strategic value of 1upt, because flanking becomes too easy.
I'm a fan of huge maps, too, and played huge PW2 script maps, which are even larger than huge terra maps (20civs). But I have to admit, while this gives a certain cool flavor to the game, some problems appear. for a very long time through the game, combat is just useless, because there's enough land left. Furthermore, half of the civs had no impact on my game whatsoever, I never had any business or war with them.
There was no such map in civ 4, either. Even modders hesitated to make maps of this size, and if, they gave instructions how to make it playable on average machines.