well i dont know if this little tut here is the "complete" answer to what your looking for, but it does teach you how to extrude along a curve. so once you learn this you should do some experimenting on your own, like taking a look at the options box of the extrude, or looking the the options of the extrution in the channel box or moving the verts like the guy does or even have it extrude as a poly instead of a nurbs. theres alot of stuff you can check out. click me for the tut