This is only one tiny feature I took out of my custom ROM project, decided to share this one right now because it might come very handy for people and it's pretty much an independent app.
What it does is placing a "Lock" bubble in place of Google Search shortcut when you press and hold the Home button and swipe up. (See screenshot below)
You should have signature checking disabled!
1. Install as a normal APK or copy to /system/app/LockAssist/LockAssist.apk
2. Press and hold the Home button (if you have Google App installed you'll see a blank bubble) and swipe up.
3. Select "Lock Assist" and click "Always".
4. Done, press and hold the Home button to see the new shortcut.