How to install/flash a ICS stock rom of any device into a different android ICS phone? is it possible to flash a stock rom of a certain device into any android device? Like for example if I have a Samsung ICS phone. Is it possible to install the default rom of samsung to a different ICS device?
No, most manufacturers interfaces are proprietary and cannot be modified to work on other devices. That being said, there have been attempts to get interfaces such as Samsung TouchWiz and HTC Sense working on specific other devices, but they are very unstable and not suited for everyday use.

HTC Sense for the Galaxy Nexus (alpha): http://forum.xda-developers.com/showthread.php?t=1535715

However, you may also be interested in specific manufacturers apps for your current rom.

S voice: http://forum.xda-developers.com/showthread.php?t=2293870