I decided to share my 3D model of the chassis exported to 3D PDF - thought that somebody may find it useful. Based on countless sessions of manual measurements of a real thing, but I don't guarantee it's 100% accurate (some areas are not fully verified yet, especially the front end). Some day I'm going to make a reproduction for myself based on this, so I'd appreciate pointing out any design errors.

DMC12_chassis_by_Rhye.PDF