WindowMargin.js

    var _Window_SavefileList_itemRect = Window_SavefileList.prototype.itemRect;
    Window_SavefileList.prototype.itemRect = function(index) {
        var rect = _Window_SavefileList_itemRect.apply(this, arguments);
        rect.height -= 100;
        return rect;
    };

    var _Window_SavefileList_itemHeight = Window_SavefileList.prototype.itemHeight;
    Window_SavefileList.prototype.itemHeight = function() {
        return _Window_SavefileList_itemHeight.apply(this, arguments) + 100;
    };

ウィンドウの余白を指定