Only open for business: Sun

Does not provide documentation on hardware such as UltraSPARC III host bridge
or Gigaswift/cassini gigabit Ethernet.

Sun does not seem to sell any systems that have source for all the drivers in Solaris.

Usually this is something major like disk or network controller.

http://www.opensolaris.org/os/about/no_source/

nge NVIDIA Ethernet
(ultra 20, ultra 40, x2100)
mpt LSI SCSI/SAS
(v40z, x4100, x4200, x4600, ultra 25, ultra 45, v440, v445, T1000, T2000, ...)
marvell88sx Marvell SATA
 (x4500)

Sun does not provide source for any SCSI drivers.
Ethernet only rge, xge, bge, dnet
Source code for very tiny amount of drivers

"I wrote the Marvell driver using the Marvell hardware specification.
The Marvell hardware specification is not publicly available and
required an NDA. Marvell has requested that Sun not make
the source available." - Lida Horn, Sun Microsystems