Google never leaves a chance to surprise us. It has unvieled the Dev Phone 1, which is fully SIM unlocked, which means that you are not bound to use the T-mobile SIM. Also, it is hardware unlocked which means that the bootloader is not locked and can use custom bootloaders in the future, if required. Also, it would let you use custom builds of Android.
However, in order to get one of these, you must register yourself as a Android developer at the Android market place, which requires a $25 setup fee too. Shipping is free, if you live in US. It is also projected to be shipped to 18 countries!