Google Chromebook will be very soon available in India. Google's senior Vice President said that he is expecting the Chromebook by early 2012 in India with a lot of features. Currently Samsung and Acer are manufacturing Chromebooks.

Have you tried Chrome OS? If not, here it is described how to run Google Chrome OS from a USB flash drive or on a virtual machine. Even you can install the OS in a separate partition with your current OS (Windows, Linux, Mac). But, since it is still under development there may be some issue with the release.