Please do not confuse this with general weight on your bike or rotating weight. I'm onto about something completely different.
Logic tells me that everytime you do a pedal stroke you need to lift your foot along with most of the legs weight on the upstroke. The heavier your foot and shoe, the more energy you need to expend to lift it. On the other hand, a heavier foot and shoe will create more force on the downstroke.
Assuming you were on a home trainer with 10kg weights attached to each of your feet how would it effect your power output and pedalling style?
What if you ride out of the saddle? High cadence vs. low cadence?