have a look to see if the pins inside the port are all fine. might be a bent on connecting to something it shouldnt also check the tiny solders where the port meets the board
If it were an issue with the ethernet port wouldn't that prohibit me from connecting to the blade via web browser to configure it?
I would think so. You have several Blades running so you have the setup down, you've tried different cables and ports so I think that would rule out anything on the net side. I would think it's related to this particular Blade, defective ethernet components?
This lists color/blinking to speed and activity.
http://pic.dhe.ibm.com/infocenter/ts7700/serv/index.jsp?topic=%2Fcom.ibm.storage.ts7740.service20.doc%2Fts7740_maint_ethernet_led.htm