Some links of interest:
Baerentzen et al. "Single-pass wireframe rendering" http://www2.imm.dtu.dk/pubdb/views/publication_details.php?id=4884
Nividia Corporation "Solid Wireframe" white paper http://developer.download.nvidia.com/SDK/10/direct3d/samples.html
edit: I see the first one was already mentioned, sorry!