DarwinPorts has worked on Darwin/x86 for ages. The prebuilt binary packages are probably PowerPC-only though, so you'll need to build from source. It's not hard; see http://www.darwinports.org/getdp/ (under the "Source Installation" subheading).
For some reason /System/Library/PrivateFrameworks/GraphKit.framework was skipped by the Tiger installer. This meant that Activity Monitor could not launch until I extracted the framework manually from the Essentials package on the install DVD using pax.
Even more problematically, the...