overet,
Few comments that might help you. Regarding your question about PCI power limitations, this document indicates that the power supply provided with the development kit may not supply enough power for some PCI devices. In order to ensure your PCI card is getting enough power, you should use an ATX power supply. Refer to section 7.2 of this document for more information.
http://www.logicpd.com/do...7/70000230_Rev_E.pdf
Out of curiousity, why do you need an additional ethernet port? The MCF54xxxFE ETX modules all have 2 supported ethernet devices onboard. Does your application require 3 or more ethernet ports?
Thanks,
-Kurt