Article: How To – Permanently Have Desktop Mode on Chrome Mobile for Android
Rooted device Instructions:
Copy the chrome-command-line.txt file attached to the post, then paste it into /data/local/ making sure to set the permissions to 755 and to remove the '.txt' file extension.
Flashable .zip, for the lazy:
You should know how to use this by now. Grab the attached ChromeDE.zip provided by XDA user djmcnz and flash away! (Thanks!) You can also drop him a thanks by visiting a post of his later in this thread.
ADB Instructions (for non-rooted devices):
Place the chrome-command-line.txt file in the root directory of your PC and rename it to 'chrome-command-line', then make sure your device is connected to your computer. When connected, issue this command:
adb push /chrome-command-line /data/local/chrome-command-line
Cheers! Hopefully we'll see a better implementation of this in the upcoming 4.2 release.