Its really a vendor decision ..... there are a number of Arm receivers (some not supported by ViX) that support hardware multiboot by basically partitioning the eMMc into mountable drives that contain E2 Images and provide the ability to select an Image at boot up time ...... this depends on the vendor e.g. Mut@nt use a different method from Gigaqblue.
Can it be done by Vu+? Well Octagon committed on the SF4008 but have never implemented multiboot - so I guess it depends on priorities and development money!