Certain example embodiments relate to a window assembly for a vehicle. A slidable window panel includes at least one top pin and at least one bottom pin attached thereto. A single fixed window panel includes a hole defined therein for receiving the slidable panel. An elongated upper rail includes first and second upper rail channels defined therein for slidingly receiving the at least one top pin attached to the slidable panel. An elongated lower rail includes first and second lower rail channels defined therein for slidingly receiving the at least one bottom pin attached to the slidable panel. The upper and lower rails are connected to the fixed panel. The first upper rail channel and the first lower rail channel are provided at a first depth and the second upper rail channel and the second lower rail channel are provided at a second depth. The slidable panel is substantially flush with the fixed panel when closed, but is slightly inwardly and laterally movable when being opened. Safety features may include, for example, teeth provided to the upper and/or lower elongated rails of the window assembly and/or a downwardly extending flange provided to the upper rail of the window assembly. Water management features may include, for example, one or more sealing bulbs provided to the window assembly and/or a draining recess or channel provided to the lower rail of the window assembly.