It seems as though this would be possible. Just from what i have read once a plant goes into its flowering stage, it has made a change in its "lifestyle" you could say and more light - torwards the end- wouldnt hurt it. If it were me i would slowly begin to increase the amount of light (so as not to shock the girl), say 5 minutes a day starting about 2 weeks prior to harvest. That would mean at a week she would be getting about 35 minutes extra light a day, and by 3, an extra hour and 10 minutes.
I would say this would be more succesful on a indoor/outdoor strain since outdoor strains may- MAY be more leniant in terms of light amount (anyone know if this is true?) changes due to the fact that outside weather (clouds, fog, etc.) could change the amount of light a plant would be getting normally.