Isn't the RESTfulness of Sun Cloud API actually addressed in Roy's 4th point:
A REST API must not define fixed resource names or hierarchies (an obvious coupling of client and server). Servers must have the freedom to control their own namespace. Instead, allow servers to instruct clients on how to construct appropriate URIs, such as is done in HTML forms and URI templates, by defining those instructions within media types and link relations. [Failure here implies that clients are assuming a resource structure due to out-of band information, such as a domain-specific standard, which is the data-oriented equivalent to RPC's functional coupling].
Example 1 Fixed resource names in a defined heirachy:
From the Sun Cloud API: "... the representation of a VDC will include representations of the Clusters which inhabit it, which in turn include representations of the VMs within each cluster."
Example 2 out-of-band information, such as a domain-specific standard:
You have to have the wiki-page contents (out-of-band information) to know that the "resource communication mechanism" for the Cloud resource field "uri" is GET.
