Then there's the Sumiko at 12g with adjustable azimuth, and the Audio Technicas, one in magnesium at 11g (I think) and three versions in their Technihard alloy ranging from 12-15g. And ZYX makes something seriously upscale at over $500. Yamamoto also offers shells in boxwood and cherry.
06-01-08: Fosse
I have the standard Dynavector headshell with azimuth (15g) an older Dynavector without azimuth (12-12,5g), Yamamoto Ebony (10,2g) and Yamamoto Tsunge (8,2g).
It's well worth the investment, which is small after all, to experiment a bit with headshells since the sound changes a lot. I dont know if the sound differs mostly because of different mass or material.I would think it's both. The difference in mass would affect it in one way and the difference in material in another. After all, let's suppose you have an ebony-bodied cartridge. You could mount it to two different 12g headshells, but if one is aluminum alloy and the other ebony, chances are they'd sound different.
It's mechanical impedance matching (material) vs. mass loading (weight). It's why some TT and mat mfrs are making platters and mats of acrylic/vinyl laminates--to get a good mechanical coupling between the LP and the mat or platter. You could use the same principle in matching headshells.