I’ve given up on trying to make CentOS 5 work with VMware Fusion. It was simply sucking too much time up with no real gains. I can’t figure out why it behaves so differently on the iMac and my Macbook.
Instead, I’ve installed Fedora 8 and mach, which is probably for the best — it gives me the freedom to build for quite a few different distributions on different platforms. The default install on FC8-64 includes a target for CentOS 5 x86_64. So far it’s building cpanspec just fine. More useful packages will come soon.