There's a 'make 3d' option in the alpha palettte...you can also try to mask it on some geometry and use the 'extract' thingy http://www.zbrushcentral.com/showthread.php?43513-Alpha-Make-3D-Minimal-Modeling http://www.pixologic.com/docs/index.php/Mesh_Extraction
What would be the best way to take an alpha like the one I've created below and turn it into an extruded object. I've thought about using the stencil as a mask, inflating the surface, but I've yet to find a way to possibly delete the outside of the surface. Still, this would probably leave me with just the front half.. i'm…