Hi Nebuka, you could do that currently by setting up a shortcut key as described here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2599.4

Then when you trigger that shortcut key, the construction plane will orient itself in the current 3D view direction so you can draw stuff in that manner and then use them as cutting objects in booleans.

To restore the construction plane back to its regular state after you are done, either right click on the View > CPlane button in the side pane, or set up another shortcut key with:

script: moi.view.resetCPlane();

- Michael