So far, rpm, smart and createrepo have been working very well for me. I don't install from source, or download from openindiana repos any more. Everything that I need, I ensure that I build using spec files and rpmbuild, and install via a custom repository on my local computer.
I've been examining build systems (Jenkins/Hudson, Koji, Go), and am about to explore the Open Build System at OpenSuse. What I'd really like to find is something that lets the developer compose build pipelines, let us trigger builds on downstream components when an upstream component's build goes green, install build dependencies before triggering a build, and optionally, let users "promote" a particular package.
I realize that not all of the above would be directly possible, but I can't help feeling that surely someone somewhere would have wanted such mechanisms in place.