I saw this on the opensolaris.org OS/Net flag day announcement alias:
With the putback of
6655597 Support for SPARC Enterprise Ikkaku
Solaris Nevada now supports the new Ikkaku model of
SPARC Enterprise M-series (OPL) family of servers.
Official product name for Ikkaku is not yet finalized.
Ikkaku is a 2U, single CPU version of SPARC Enterprise
M-series (sun4u) server utilizing the SPARC64-VII
(Jupiter) processor.
All I know is what I've read on opensolaris.org, but if you'd like to learn more, try searching for Ikkaku on opensolaris.org.
By the way, according to the announcement, Ikkaku is Japanese for Narwhal.