They seem to have eliminated S-series for 2011 but you can still find them online. Near as I can tell the 10 and 40 series in the new line up would be comparable.

Edited to add: I found this on http://blog.treefortbikes.com/index.php/posts/651 from December:

40 Series


S –series and XX headsets are completely removed and they are replacing them with the 40 Series. All upper and lower sections are sold separately in order to allow for them to accommodate the 30 different tapers that are currently in production with frame makers. They are able to handle 95% of these combinations with 4 tops, 2 bottoms and a couple of conversion crown races. They combined all of the good features from the two previous series and trickled down technology from the 110 family. One nice feature for the home mechanic is in the captured compression ring they use which gets rid of some of the headache during install. Overall this group is much improved and they kept the price the same, which is always nice!