It can certainly be done and featured heavily in one of BA's recurrent sim checks about a year ago. From what I can remember the spoilers will automatically stow when TOGA is selected and you may get a config warning as the aircraft thinks you are trying to take off with flap 25 but apart from that it's really no big deal. There's no greater risk of a tail strike than a normal take off and you really shouldn't be below Vref at any stage of the flare!