It's true that you won't have any trouble finding them if you use general search capabilities, but I wanted to warn you that many are no longer located in the Sedums Database. Here's the "M" page if you search by genus, for instance:
http://garden.org/plants/brows...
Here's the "M" page if you search by parent plant:
http://garden.org/plants/brows...
Only 3 of the 14 cultivars currently discovered in a general search are still in the Sedums Database.
Julia, I haven't run into any articles dealing specifically with Sedum. This is just a matter of scientific progress. DNA testing is now available to botanists, and as they test various plants, they find similarities or differences that can assign them to different species and even to different genera.
Some genera have disappeared completely. We once bought plants of the Lychnis genus and plants of the Silene genus, but botanists have discovered that all of the Lychnises actually are Silenes, so Lychnis no longer exists as a genus.
A change that might be more pertinent to people in this forum is the disappearance of the Jovibarba genus. All of the Jovibarba species have been reclassified as synonyms for Sempervivum species, so that's another big job that has to be done.