FYI - we designed a universal enclosure which accommodates the Arduino and several other development boards from Olimex and the NGW100 from Atmel.
You can buy it at Sparkfun: Chameleon 1 Enclosure - Black (Sale) - PRT-09331 - SparkFun Electronics
We should design a faceplate for the arduino with popular shields, but haven't done a faceplate for a shield yet, just arduino. If you have popular shields in mind that you would like us to support, you can send me a PM or tweet me at @ESawdust.