Bin4ry XDA's Recognized Developer made a small script which is able to root ICS/JB phones. It uses a remount timing issue in Androids "adb restore" service.
So normally it should work on nearly all ICS/JB devices, for some it won't but the idea may work in a slightly modded version

There is a case for Xperia T and Xperia S,P etc. phones, this phones run ICS but don't have android's native restore with adb, Sony has added a own custom "Backup&Restore" app, the script handles this cases too, just choose the correct option!

How-To:
1.) Download attached file.
2.) Extract it using 7zip
3.) Double click the RunMe.bat and follow instructions!
Xperia phones = Normal mode
Sony Tablet and similar = Special mode


Video Tutorial:
 

Notice:
Normal Mode will not wipe any other data, dont worry!
Special Mode CAN wipe your data, Rollback SHOULD restore, but to be sure backup you data somehow!

Xperia T Firmware .195 is not rootable sorry!
This is same for other Sony devices with new Firmware like .2.55
Sony fixed the bug in current firmwares and so we have no chance with this particular method!

Confirmed devices:
Sony Xperia : S, T, P , Acro S, Ion , Tipo , Tablet S, Go, Sola, U
Google: Nexus 7 [UK Firmware] (thanks Paul O'Brien for test) [seems some firmwares to work and some don't, as i dont have this device myself i would appreciate reports with FW-versions]
XTouch: X401
Jiayu G2-S thanks txakar
LG: P705 thanks mariolcneto, P7510 thanks fdothivanka
HTC: One S thanks sebagsm, Sensation XL [ICS 4.03] thanks Koate via PM, Sprint's OTA ICS update on Evo3D seems incompatible, Desire S thanks to Krayt via PM
Kyocera: Rise & Hydro thanks jmztaylor
Samsung: Galaxy S2 thanks danroob
Some more
Ainol: Novo 7 Tornado 7 thanks anoperson
Prestigio: MultiPad PMP5197D 9.7 ULTRA thanks logofreax
HDC: I9300 S3 clone thanks PMmshprojects

Additional info for SONY 2012 Owners:
If your STOCK ROM does not have preinstalles Sony's Backup&Restore app then download it from attachment 


Download Root_with_Restore_by_Bin4ry_v18: Click