I would have to say no because the viruses also affect the strength of the plant. Viruses cause "color break" (looks like tie-dye) in orchid flowers, and it took many years of breeding in order to duplicate the effect genetically (without the viruses), but I have never heard of such viral infection actually being wanted or induced.

The problem (well, one) with viruses and variegation is the "splotches" caused by viruses tend to be randomly present rather than clean lines/edges that's more desired.