I come across some hints on changes in the the next Solaris 10 update probably scheduled around April, /10? It looks like the zpool will be lifted to version 19 which would mean the following new high level features:
17 Triple-parity RAID-Z
18 Snapshot user holds
19 Log device removal
This would mean there would be no zpool deduplication in the next Solars 10 release, but that is not much of a surprise given that it was just recently integrated into ON. Triple-parity raidz and log device removal will nevertheless be a good addition while keeping the risk low.
It also looks like a iSER (iSCSI Extensions for Remote DMA) backport are in the works for this release.
Two additional 10G NIC drivers have mentioned update 9 integration in their respective PSARC:
Emulex PCIe converged NIC driver [PSARC/2009/526]
qlge - QLogic PCIe converged NIC driver [PSARC/2009/525]
Samba update to 3.4 also looks like it's aiming for this release together with iSCSI boot and Firefox 3.5.
Update2: The name for this release and additional features of ZFS is mentioned in a later post here.
Talks I have given
5 months ago