Conventional wisdom says the motion is greater in the bow and the higher up you are (higher decks). I cannot confirm this as the weather was very different on the 2 cruises we were on (#1 - deck 2 mid ship; #2 deck 8 bow). We noticed significant motion on cruise #2, but there were 18 foot seas - my wife did get sick, but she is prone to motion sickness - none of the rest of us (me 2 kids - 7 and 4) were impacted.
Bow vs. stern - it does stand to reason that the bow would "bouce" more than the rest of the ship as it cuts through the waves.
Top vs. bottow - again, stands to reason that the higher you are on the ship, the farther you are from the center of gravity, so you would experience more side-to-side movement (like the end of an upsidedown pendulum).
I cannot confirm this first hand (no motion on cruise #1 - very smooth weather), but the physics seem to make sense.