The Colony/Junk Yard Wars Gmod Idea?

After watching most of season 1 of the colony, the show gave me a really good idea for a survival/build game mode for Garry’s mod. Not only did the survival aspect of the Colony generate the idea in my head, but so did building they do throughout the season, which also reminded me of Junk Yard Wars that use to be on TLC here in US about 8 years ago. But the only thing is, I have close to zero experience in doing anything in the nature of constructing such a game mode. Which has lead me to a few questions?

Has the been done?
Is their anything close to this already?
How would you go around making a game mode?

[editline]06:37AM[/editline]

looks like a good map to be done on
http://www.facepunch.com/showthread.php?t=614509

[editline]12:51PM[/editline]

Why does nobody read the sticky?

fuck that shit