MakeCube is a Animation Master plugin that simply creates cubes. It supports bevels and different x, y and z sizes for the cube.
Latest version tested with 11.1h
Installation
Download the plugin from here and copy .hxt file into your plugins folder.
If the plugin fails to run you may need to install the VC++ support DLLs. Download these from here and copy them into your Animation Master folder (the one with master.exe in it).