Initials Necklace
I had this printed via Shapeways in sterling silver.
Not providing an STL because you will want to customize the lettering.
Open up the .scad file in OpenSCAD and create your own version. If enough people like the design I may build a customizer version.
The initials are made by saving individual letters as DXF files from Inkscape, but you can probably use system fonts in OpenSCAD using this method. http://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Text