There is a PSARC awaiting approval for providing on of the most long standing enhancements requests for Solaris Zones: NFS Shares from within a local zone. This functionality will not be limited to NFS and will initially also support CIFS. It seems to be planned for Solaris Next only, so no backport to Solaris 10.
From the PSARC:
"Patch binding is requested; however, there are no plans to backport any of
the proposed changes.
The proposed changes are needed to support an NFS server in a non-global
zone; however, the changes are not specific to NFS. They would also be used
when enabling any file sharing protocol (ie. CIFS) server for non-global zones."
Talks I have given
2 weeks ago