According to a quick glance at the files downloaded for the Beta client, there are something around twenty(!) equipment slots, including what seems to be two ring slots (also reported as four from some sites, but the current version of the beta client leads me to think two), and a bracelet slot (possibly two of those as well).
What is more interesting, to me, is that data is included to make accessories visible, down to earrings, necklaces, and rings. This will add a subtle depth to the environment that FFXI was unable to achieve due to resource and software limitations.
*The following paragraph is intended for computer geeks, read with caution.*
As for the files themselves, they seem somewhat obfuscated. From what I am going to assume, the folders in the data areas are actually treated as files , and the numbered, extension-less files within those folders are stitched together by the client to read the data (as an example, folder "hir_mdl" would be treated as a file/container/wrapper "hir.mdl", and files 0001 and 9999 within it would comprise the data). This is, presumably, to make data mining more difficult. If you decide to delve into these folders, MDLs are models, TEX/TEX1/TEX2s are textures to map onto the models. That is the case within the /client/ directory. Within the /data/ directory, you will find the much more familiar hex numbered folders leading to .dat files, a la FFXI. Nothing of value is human-readable in these after a quick glance; I am going to assume that old .dat viewing utilities will not work, but I may be wrong.
Just felt like nerding out there for a bit, this is only speculation on the first release of the beta, so of course change is to be expected.