Received a nice Thinkpad T23 to try to fix the cardbus adapter issue with these machines. It only took me around 4 hrs to track the problem down. The open command on the adapter takes anywhere from 5 - 40 seconds to complete and during this time there is no activity on the pci bus. So the bios power management system decides to put the adapter into a sleep state, and, of course, as the adapter is in the sleep state we never get the open completed interrupt.
I already have a really nasty hack to get around this, but it holds the kernel hostage during the open command. As this may be a 40 second period, that's completely unacceptable. Over the next few weeks I will be delving into the olympic tech docs and the pci power management specs to try to come up with the correct solution (i.e. somehow tell the bios not to power down the adapter).