Approach to making a 2D graphic 3D? I've been given a logo graphic that is solid black, in 2D.  The best way to describe is to visualize a musical treble clef drawn with a wide-tip pen slanted. There are two important characteristics that I'm trying to figure out how to model using Blender (2.69): 1) The wide-tip pen (calligraphy style) causes the width of the stroke to change continuously, and 2) the stroke crosses over itself twice.  The 3D request is to have the stroke be "raised" in the middle.

I have the outline of the logo traced perfectly with a bezier curve, but I can't figure out how to give it a smooth contour that changes height to match the width of the stroke.

Conceptually I'd like to extrude a bezier circle along the outline, scaling each extrusion to match the width of the stroke.  When done I'd bring a plane in and have it bisect the model between a lower or back half and the upper or front half.

But every way I've tried to extrude a bezier curve results in the curve just moving along with my cursor.  I was hoping to use bezier curves to keep the quality of the curve high until I was done shaping the entire model, then convert the curve to mesh and clean up where the stroke overlaps.

Perhaps a workable approach is to create a circle mesh, extrude it, rotate as needed, and scale it, then repeat all along the outline. However, I absolutely have to avoid faceted curves as the "skin" flows around the stroke.

I am hoping someone more experienced with Blender would have a helpful suggestion or two.
Try this: Extrude your outline to create a "flat topped" shape. 

Switch to a side view and create a curve that describes the peak at the "stroke cross" the way you're visualizing.

Extrude your profile view curve along the horizontal axis to create a shape that intersects and contains your logo.

Boolean intersect.