Using the unofficial spore 1.7 patch you can modify save game worlds allowing for some awesome custom homeworlds. Here is an Example
. Here is how to do it. First off make sure the unofficial spore 1.7 patch if installed. Next, you want to make a space stage save. Then get to where you can leave the solar system and enter the console using CTRL + SHIFT + C and type the command spacecreate (Spore patch 1.7 also makes space create supply every tool.) Now, find your save file's position in the galaxy and go there. Then you will be on the save file's planet. If you colonize the planet the save will be of the colony placed there to fix this simply destroy all of the colonies you place. Now, feel free to customize the home world using space tools. You can make your homeworld t0, color the skies, oceans, and land, and/or change flora and much more.