Have you seen the Freetronics EtherTen? Its basically an Arduino UNO plus the Wiznet Ethernet Shield combined into one (SD card slot included). It also supports Power over Ethernet, both a cheap version of PoE and the official version of PoE.
I bought one to act as the controller for a zigbee network and it took almost no time to load the standard web server example sketch and get it running (the one that returns readings from the analog pins).