I doubt you'll find a new seal for sale. I'd just keep rolling with the Lizard Skins and repack annually, maybe twice a year if you ride in the rain a lot. If you ever need to replace the Lizard skins, just cut a section of tube, remove stem and slide the tube section over top cup area.

The bearings will likely last for years like that.

Oddly enough Cane Creek sells top half of headsets. I think the S3 is probably what your bike needs, make sure first. But you could probably get a whole headset for not much more.

http://www.pricepoint.com/detail/211...t-Assembly.htm