How can I make a new body shape in blender?

[mauvikinz]

I don't really like the body types out there now, and I have a pretty good one in mind, but I don't know quite how to make a new body type for the sims 2... I'm pretty good with meshing, but I kinda just want to be able to edit the in-game body mesh to my liking (which willl mean completely changing it XD) so that I don't mess anything up with the seaming...
Yes, I know I probably sound stupid, but please :help:

[Skimmer55]

Follow this (http://www.modthesims.info/showthread.php?t=248699) tutorial to give you an idea. and you will need these (http://www.modthesims.info/d/246658) tools :)

[mauvikinz]

Follow this (http://www.modthesims.info/showthread.php?t=248699) tutorial to give you an idea. and you will need these (http://www.modthesims.info/d/246658) tools :)
Thank you! You were a big help.