Manually Updating your OS? Is it possible to manually update any Android Device?
Yes, assuming the device has been rooted and someone has engineered the update to work with your specific device.  How fast that happens depends on how hard the devices manufacturer has made it, and how active the community is.  Its not as simple as just loading windows on a computer.  

I asked a similar question a while ago. Check out the answers for more detail: What is involved in installing Android onto a device?