System Information
Windows 64
Two GTX 580

Blender Version
blender-2.70a win64 hash f93bc76 not working
blender-2.71 win64 hash 9337574 not working
blender-2.71 win64 hash 6891f1c not working
blender-2.71 win64 hash 9460fe3 not working
blender-2.71 win64 hash c670ceb not working
blender-2.72 testbuild1 win64 hash d919218 not working
blender-2.72 rc1 win64 hash eb464ee not working
blender-2.72 win64 hash 0334be9 not working

Short description of error
Using a Vertex Group within the Solidify Modifier seems to generate reverse normals and shading errors outside of the vertex group

More likely generating faces over whole mesh, instead of vertex group and adjoining vertices?

Exact steps for others to reproduce the error
Add a cylinder, in Edit mode select the top two rows of vertices, add a vertex group, return to Object mode, add a Solidify Modifier select the vertex group, none of the available settings correct visible reversed (overlapping?) normals outside of the vertex group.

Alternatively, open attached Solidify Modifier Vertex Groups unexpected result.blend

**In the file:*
Left objects Flat shading, Right objects Smooth shading
Front row: Solidify modifier with vertex group
Middle row: Solidify modifier without vertex group
Back row: no modifier

Search results seem to indicate previous reports used more than one Solidify modifier, that is not the case in this report.

Thank you,

David

PS: Fresnel node only added to help highlight reversed faces during Cycles render