Here is an Android 4.2.2 Jelly Bean rooted firmware for the PIPO M8 PRO tablet (3G model) based on latest official update from Pipo dated 2013/05/18

(update-M8PRO-3G_chinese_version_android_4.2_20130518.zip)

Kernel: Linux version 3.0.36+ (root@wzq-G41M-ES2L) (gcc version 4.4.3 (GCC) ) #115 SMP PREEMPT Sat May 18 09:25:04 CST 2013

Android 4.2.2 JB: M8pro/M8pro/M8pro:4.2.2/JDQ39/eng.root.20130516.105208:eng/opinions-on-teclast-p90hdst-keys

Custom firmware features:

• root with latest SuperSU version 1.30 (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

Download: kasty-pipo-m8_pro_3G-422-20130518-rooted0.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.