Google created Honeycomb to run tablets, but the company has made it clear that it has no intention of maintaining and running parallel OSes to run on different devices. With Ice Cream Sandwich, Google is adopting one OS for all approach -- an OS which will run on various form factors and devices including the Google TV.
This is one of the reasons Google is holding the Honeycomb code to discourage vendors from putting it on smartphones and create a bad experience for users.
Honeycomb users might wonder how will honeycomb look like on smartphones. Well, it appears that even if the code-base is same different devices will have different interfaces optimised for the screen size and devices. No one would want a smart-phone-targeted Gingerbread interface on Xoom.
We got a hint by this blog which has been able to 'expose' the hidden Gingerbread interface in Honeycomb. The OS changes the interface from Honeycomb to Gingerbread if it detects a higher screen density.
If you have a rooted tablet you can change the LCD density from 160 to 170 and you will be greeted by the Gingerbread interface on your tablet.
Fun never stops at Google!