As the title says, could someone please make a mapscript that creates marsh/swamp planets?

Right now, maps with mostly marsh tiles can only be created via the skirmish map script, which isn't even available in RT by default and also doesn't create a "realistic" planet.

Ideally, I imagine it to look like this:
-protean or terran landform with a tiny ocean, since dealing with marshes should be the main challenge
-mostly marsh tiles
-lots of rivers and some small lakes
-some forests
-some plains
-a few hills here and there
-little grassland
-very little mountains or canyons, marshes slow down enough
-very little to no tundra, only at the poles if possible
-no desert
-no snow


Why a marsh planet?
-It's not possible to create a marsh planet with the standard map scripts (except skirmish)
-Having a lot of marshes on a map creates an interesting challenge for the player. You need more workers and time to make the planet fertile and defending against attackers is more difficult due to the 15% combat penalty on marsh tiles, which makes an offensive playstyle more rewarding. Additionally, marshes (and forests) give a movement penalty, so fast units are less effective here.
-Combined with the lush biome in particular, a marsh planet looks quite unique imho.
-Having more different planets to land on is always a good thing =)