The Library of Congeress holds the master wax cylinders, but there are copies in England at EFDSS, and apparently at Leeds, where Julia Bishop is in charge of getting the recordings salvaged as near as possible. At my prompting she gave a generalized statement about progress in the restoration project about 6 months ago on a subscription newsgroup in England. Malcolm Douglas, here, has obviously heard some restored recordings that I know nothing about.
A JPG of Julia Bishop, and Jennifer Cutting of the Library of Congress
Folklore Archive, displaying some of Carpenter's discs can be seen at the bottom section, Images, at www.erol.com/olsonw. I am certain that Malcolm can tell us more, if he will.