Graffiti Kingdom in Blender

Recently, I have been playing this game called "Graffiti Kingdom" for Playstation 2. It is a perfect game for me since I can draw whatever I want, and make it as ridiculous as possible, ergo little winged lizard dudes running around with giant laser cannons and spaceships that breath fire, shoot rockets, and have Trogdor arms. It's a simple platforming game, but the customization end is what attracts me; you can configure your own character (or any monster you capture) with a few types of attacks, similar to the attacks in Hybrid Heaven for the Nintendo 64.

Either way, one thing I found particularly interesting was the ability to draw a 2D curve, like a trace, and then the program automatically turns it into a 3D shape via extrusion. However, it also does this in a way that promotes more organic looking shapes, which led me to this thought:

I would like to make a python script in Blender, that does the same thing; You simply draw a closed shape, and it automatically guesses at what shape you were trying to draw. This is done by most modelers manually, and is a very quick way to model organic shapes. I figure, if I could speed that up it would encourage some of my other friends to "sketch" a quick 3D shape of whatever they were trying to tell me with a 2D drawing.

So far, the script is OK for drawing a 2D shape, but I am having trouble deciding how to make the shape '3D'. As soon as I figure out how to upload stuff, I'll post a link.