Did you mean something like this:
http://forum.openscad.org/file/n16019/spiral.png

The things that twist does are a little weird; I don't think there's an easy
function for doing that sort of thing. Here's the code I used to make the
image above:

use <path_extrude.scad>;
h=6;
rad=8;
loops=1.5;
sph=40;
myPoints=([[4,-h],[0,-h],[4-2h,0],[0,h],[4,h]]);
myPath = [ for(t = [0:10:359]) [
radcos(loopst),
-radsin(loops*t),
t/360 * sph
] ];
path_extrude(points=myPoints, path=myPath,
merge=false, trimEnds = false);

Which needs my path extrude script as well:

http://www.thingiverse.com/thing:186660

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Nice solution. However, I could not achive the same clean design when the
spiral axis is the Y axis:

myPath = [ for(t = [0:10:359]) [
radcos(loopst),
t/360 * sph,
-radsin(loopst)
] ];

It seems that path_extrude is not affine invariant.

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