We have found 2 bags that match these dimensions.
53x30x22cm 20.8x11.8x8.6"
linear: 105cm/41.2" 31.5L
The bags below are not exactly the size you were looking for, but perhaps you'll come to like them.
46x29x20cm 18x11.5x7"
linear: 95cm/36.5" 24L