KDE on OpenSolaris is like Projects/KDE on Solaris but with some extra setup steps. There are IPS packages available intermittently, when the KDE IPS package server is up (it's a VM at the end of a DSL line - see the archives of email@example.com to find it). Using OSOL as a build platform is possible, but you'll need at least one Nevada machine as well.
The current KDE4 IPS package server is the machine pkg in the domain bionicmutton.org; the IPS server runs on port 10000. This is a fairly standard IPS setup. The bionicmutton domain is Adriaan's and has been previously used to serve up SysV packages as well. The IPS server is in a VirtualBox at the end of a DSL line, so it's not necessarily up or fast. Eventually we will be moving to a more convention IPS repo like pending/ or contrib/.
First you need to set up a pkg authority to be able to get packages from bionicmutton at all. The first line creates the authority; the second fetches a catalog from it and the third checks that at least one of the packages can be found. Only the first is strictly necessary.
pfexec pkg set-authority \
-O http://<host.domain>:10000/ bionicmutton
pfexec pkg refresh bionicmutton pkg search -r KDEgdm-integration
pfexec pkg install KDEbase-apps \
After installing KDEgdm-integration, you should be able to log out and choose KDE as a session type from the login manager. Then you get a full KDE 4.1.3 desktop. On my machine with Radeon graphics it is very slow to start up and launch applications, but fairly fast after that. There is a discussion on performance tweaking on firstname.lastname@example.org.
You will need a Nevada machine as well. Set up SunStudio 12 and patch it up as described on the Projects/KDE on Solaris page. Tar that up and then extract it on your OpenSolaris machine. This will give you /opt/SUNWspro. Leave that alone.
OpenSolaris ships without many of the development tools you will need. Start by installing development headers and tools:
pfexec pkg install SUNWmercurial \
SUNWgmake \ SUNWcurl
pfexec pkg install SUNWhea \
SUNWaudh \ SUNWxorg-headers
Create directories ~/src and ~/bin. You are going to need these in the rest of the development environment setup.