The official Dell slides leaked on reddit confirm the slimmer and smaller chassis on the Precision 5750, as the mobile workstation will be fitted with 92% display/body ratio IGZO screens. Specs include Comet Lake-H or Xeon CPUs with up to 64 GB of DDR4-2933 RAM, up to 4 TB dual NVMe storage, Quadro RTX 3000 GPUs and 4x Thunderbolt 3 connectors. The XPS 17 9700 should get similar specs except it will not get the Xeon and Quadro options.
https://www.notebookcheck.net/Dell-s-17-inch-Precision-5750-mobile-workstation-and-similar-XPS-17-9700-gaming-model-get-leaked-specs.462244.0.html