Tom Chi, one of the guys behind Google Glass spoke about prototyping the device at TEDYouth. He discusses how the company was able to speed up the creation process via "rapid prototyping". He says it only took them one day to come up with the prototype (this was done with clay, paper and modeling wire). They were able to prototype projections for the device in 45 minutes.
In actual Google Glass-related news, a headset with bone-conduction speakers was revealed in a recent FCC filing.