I have designed a map recently which I have not had a chance to play. I suggest it here for a possible future GOTM. The description here is from memory. More details will be provided if the map is picked for play.
This world is 40x250 round. It consists of 256 isles. Each isle is a 2x2 square. Human player plays purple and starts on one such isle near the south pole. There is another such isle within a trireme's reach a little bit further to the South. Orange player is a little further north (not reachable via trireme) and starts on 2 such isles connected together at the tip. The cyan player is north of orange, again out of trireme's reach, and his homeland consists of 4 such isles. The yellow player is north of orange, again out of trireme's reach, and his homeland consists of two close by land pieces each made of 4 such isles. This pattern continues and culminates with the white player having a homeland of 64 such isles. The remaining 128 isles are near the north pole.
The isles each have 2 grass tiles (512 total) and one plains tile (256 total). The remaining tile is distributed as follows:
128 forests, 64 hills, 32 deserts, 16 swamps, 8 jungle, 4 tundra, 2 mountains, and 2 glaciers.
No grass tile covers a special.
Just to make it more challenging, the human starts with one settler and no techs. Orange player gets 2 settlers and 1 starting tech. Cyan gets 3 settlers and 2 starting techs, ... White gets 7 settlers and 6 starting techs. No starting tech will allow the building of a wonder.