easyjet A321,
Pretty unlikely. Whilst there is some point-to-point traffic on EK's MAN-DXB route, the key to the service's success is access to the huge wave of EK connections to points beyond. As a competing carrier, Virgin is unlikely to be offered unrestricted interline access to this extensive EK operation. The Virgin A333 would have to rely principally on DXB terminating passengers - are there enough of these, especially with EK (and EY down the road) selling seats too?
Virgin does codeshare ex-MAN with Singapore Airlines, so they could conceivably cooperate with them via DXB. However, SIA have their own scheduled service linking MAN with Asia/Australasia, so it is difficult to imagine that they would encourage a VS operation to DXB.
So, VS on MAN-DXB? Sadly, probably not. My two cents worth anyway!