Is there a mod like this out there? I recall downloading a map that had Odyssey speed, which was Marathon speed, Epic production. But I want something faster :( If this exists, point me in the right direction? If it doesn't exist, can someone tell me how hard it would be to make the modification myself?

EDIT: And to clarify, by epic speed I mean the years go by slower/more turns/higher tech cost. My mistake.

Super easy to Mod yourself.

go to the file Assets/XML/Gameinfo/CIV4GameSpeedInfo.xml

it lets you pick how much extra percent is required for techs, production etc in various speed levels, just change what you need. Also, you can fiddle with the number of years a "turn" represents