While I'm new to this forum, and it's easy to assume the newbie doesn't know much, I can assure you this isn't my first time around the workbench. Even won some design awards many moons ago in Nuts and Volts...
I was hoping someone had some advice on validating proper Ethernet Shield operation at the SPI level as the Arduino Ethernet library, even in 1.0, does a very poor job of providing feedback on what's happening inside the w5100. This may be beyond the scope of the regulars here though, I'm guessing. I'll pop over to adafruit's board and see if anyone there has messed with the 'duino Ethernet Shield.
Thanks for trying.