Why do you need a metal body for grounding? The ground conductor and/or shield can usually be taken through the connector?
The only other reason I can see if using something like flexible metalic conduit, and Thomas & Betts (T&B) have an adaptor to transition from conduit thread to MS style connectors.
If just using flexible cable, I cannot really see the reason for not using something like the AMP CPC connectors.
The MS style connector are nice, but not cheap.