Here is an Android 4.2.2 Jelly Bean rooted firmware for the PiPO M8 PRO (model without 3G module) it is based on latest official update published on 2013/11/11.

( update-M8pro_chinese_NO3G_20131111.img / M8pro software_NO 3G_chinese version_android4.2_20131111 )

Build information:

Kernel: Linux version 3.0.36+ (root@alex-System-Product-Name) (gcc version 4.4.3 (GCC) ) #282 SMP PREEMPT Tue Sep 17 14:38:20 CST 2013

Android 4.2.2 JB: rk30sdk-eng 4.2.2 JDQ39 eng.root.20131111.151640 test-keys

ro.rksdk.version=RK30_ANDROID4.2.2-SDK-v1.00.00

Notes: 

- Certificate Center and original PiPO launchers have been kept in the firmware

- Certificate Center will ask for product key, which is not needed, just hit later and connect to Internet and it will be activated

- any update received thru OTA may interfere with our custom firmware, we recommend not to apply any OTA update

Custom firmware features:

• root with latest SuperSU version 1.65 (free version)
• removed most Chinese and unnecessary applications
• Google Play Store fixes so more application are visible/compatible
• updated busybox v1.21.0.git (2012-11-29)
• Unix like init.d boot scripts support, more details on init.d scripts here
• changed permissions on external sdcard to allow write access
• increased space for applications (/data partition) to 4 GB
• kernel modules (cifs, tun, lan, serial, xpad) compiled by Oma & Crew RKTablets, thank guys!
• NEW! : optional ClockworkMod (CWM) Recovery easy install package
• all launchers have been kept: stock Android, Kid Launcher and PiPO launcher

Download: kasty-pipo-m8_pro-422-20131111-rooted4.zip

Flash with Rockchip Batch Tool version 1.7, use Restore button.

Please report any problem with this firmware, I can't verify this custom firmware works as I don't have a PIPO M8 Pro tablet to test the custom firmware.