3D-Printable 3U Rack Frame Design

I need a 3D-printable 3U rack frame that holds four NVIDIA DGX Spark computers (each 150 × 150 × 50.5 mm, 1.2 kg) and their four power bricks (100 × 100 × 35 mm, cables exiting both ends, needs ~180 mm end-to-end clearance) in a Ubiquiti UniFi Toolless Mini Rack. This rack is not a standard 19" rack: devices sit flush between the posts in a 450 mm opening, resting on removable L-rails (20 mm lip, 25 mm web) and clamped by the rails' M4 thumbscrews, which land 42 mm behind the post face and 8.5 mm above each lip. The Sparks load from the front, mesh face forward, ports to the rear, arranged two wide by two high, with airflow unobstructed. Deliverables: STEP and STL files split to fit a 256 mm Bambu Lab X1C bed, designed for ASA with heat-set inserts, plus a hardware list and assembly drawing. Existing open-source starting points I can share: Mixmeister's "NVIDIA DGX Spark 19-Inch Rackmount" on MakerWorld and my current parametric Python/STL set, which works but needs cleaner assembly access and finishing. Budget and timeline negotiable; please quote fixed price and show examples of functional printed mechanical designs.