I don't think they would. But dark themes should draw less power because less pixels are turned on, or at least that's what my puny mind can deduce.
At the end I would not worry about themes in general.
What consumes additional energy is vibration. Turn that off. And GPS. And WiFi. And Sync. And scheduled app checks. And go low on the display brightness.
after I try widgetlocker lockscreen, and SPB shell 3D, I can say yes these apps consume a little more battery, FYI I am using black tsf background for these tests.