You know making a map like that is so simple.
Start a new game with the desired map size, then immediately go into world builder and change all plots to oceans. (This will remove all players from the game so you will have to put them back before leaving the WB.)
Once the map regenerated with all ocean, do the same thing again but this time change all plots to grass. After the map regenerates, add the start places for all of the civilizations in the game you want and exit.
This will of course give you a map without forests, rivers, or resources. Now, open up the menu and go to game tools. I think it's the bottom option. Might be called something else. However, in there you'll see it have a check box that says Enable Debug Tools. Check it and click ok. Then hit ~ which will open the console. From here you can give commands to finish the map.
Type: Game.toggleDebugMode (this will enable debug mode)
Then Type: Map.generateGoodies (randomly places goody huts)
Then Type: Map.generateBonuses (randomly places Bonuses)
then type: Map.generateRivers (places rivers around the map.)
Each Map.generate... thing will take a momment or so to generate, so be patient as it can take a min or two depending on the size of the map.
Once you are done that, you can go back into the world builder if you wish to place some forests. I believe that you can do that by typing something also. It could be Map.generateFeatures but I am uncertain. Of coursed you'd have to be in the console to do that not the WB.
Once you have your map and are satisfied with it, uncheck the debug tools box, and save the game. Exit and then reload it and you'll be able to play from there. I suggest this because without leaving you'll see the entire map and what each AI opponent is researching. I never enjoyed seeing that and it also makes the turn sequence much longer if the entire map is revealed.
I hope this helps. It might seem like a long process but it shouldn't take you more than 10 min to do.
