The Paranoid Android 3.0 ROM Release Candidate started rolling out to selected devices earlier today. You can now download PA 3.0 Mako ROM and install Paranoid Android 3.0 on Nexus 4 device of yours. Since it is a custom ROM, you will need to have a rooted device with custom recovery installed. So, you will need to root nexus 4 4.2.1 first and then install the custom ROM. Follow the steps provided below:
How to Install Paranoid Android 3.0 on Nexus 4 (PA 3.0 ROM for Mako)
Please take a backup of your data as you will lose it during the process.
Step 1: Download the ROM (direct download link): pa_mako-3.00-08FEB2013-175549.zip
or download the latest version for your device from here: goo.im/devs/paranoidandroid/roms/mako
Step 2: Also download GApps for Paranoid Android ROM as its not included in the ROM.
Step 3: Copy both the downloaded files on your SD card.
Step 4: Boot your device in custom recovery mode (CWM / TWRP Recovery mode).
Step 5: Wipe your data using wipe data/factory reset option in CWM recovery.
Step 6: Flash both the files (ROM & GApps) one by one and then reboot your device.
For those who are new to this and find the instructions difficult to understand, we have posted a detailed guide on how to install custom ROM using CWM Recovery.