Here is an Imperial Guard Engineers conversion from Simon’s collection.
These conversions were made, probably about ten years ago.
It’s the hull from a Deathstrike Missile Launcher with the “claw” from an Ork Battlewagon.
From a fluff perspective, it can be easily imagined that an Ork army overtook an Imperial Guard tank factory and utilised many of the components including cranes on their own tanks and battlewagons.
Of course calling it an AVRE is a bit of a misnomer as I guess the Imperial Guard don’t have Royal Engineers, or do they?