Yes, the extra probes are already OSS. DTrace is already OSS (CDDL), as is the whole Solaris
kernel, including ZFS.
The OpenSolaris OS is mostly OSS, except for a few programs. Work is underway to eliminate
that (for all I know, there could already be a distro that ships the CDDL kernel with a 100%
OSS userland).
http://www.opensolaris.org/os/downloads/
The packages available for OpenSolaris tend to be crufty (old, not much selection if you are
into 'new' tools such as nginx or git.)