Here is an Android 4.2.2 Jelly Bean rooted firmware for the PiPO Ultra 2 (Pipo U2 aka DS717) tablet. This custom firmware is based on latest PiPO release dated 2013/12/04 which, based on the signatures, seems to be mainly a kernel update.

(update_U2_#446_chinese_20131204.img)

Build information: 

Kernel: Linux version 3.0.8+ (root@lzj-desktop) (gcc version 4.4.0 (GCC) ) #466 SMP PREEMPT Wed Nov 6 11:07:42 CST 2013

Android 4.2.2 JB: PIPO/DS717/DS717:4.1.1/JRO03H/20121213.183452:eng/release-keys

ro.rksdk.version=RK30_ANDROID4.1.1-SDK-v1.00.00

Custom firmware features:

• root with latest SuperSU version 1.93 (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
• disabled OTA updates (may cause problems, see Notes below)
• kernel modules (cifs, tun, lan, serial, xpad) compiled by Oma & Crew RKTablets, thank guys!
• NEW!  optional ClockworkMod (CWM) Recovery easy install package

Notes: 

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

Download: kasty-pipo-u2-422-20131204-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 U2 tablet to test the custom firmware.