The problem Michael will have with a combined extrude cut is that the complexity of the command can be high. Inventor and Solidworks do this already but there are a LOT of options to consider e.g. is the end face of the extrude flat or the same as the original surface, is the extrusion parallel, drafted or perpendicular, what do you consider the terminating surface to be, etc, etc. Effectively, you are combining a host of simple commands in to one, with a host of options.

The advantage of doing this in Inventor or Solidworks is that they are parametric, and this type of combined command only creates one feature in the history tree, making future manipulations, such as variants easier, and can be driven by variables that are common across the tree. As MoI doesn't have a parametric history tree or variables, I'm not sure what would be gained.