We have found 22 bags that match these dimensions.
50x32.5x17cm
35L
The bags below are not exactly the size you were looking for, but perhaps you'll come to like them.
47x26x14cm
36L
40x30x15cm
28L
48.5x28x16cm
26L
47x27x17cm
~22L
42x30x17cm
21L
42x30x15cm
40x28x16cm
linear: 84cm 18L
43x28x14.5cm
~17L
38x27x13cm
linear: 78cm 16L
40x32x15cm
16L
36x30x15cm
linear: 81cm 14L
36x31x13cm
14L
35x25x16cm
linear: 76cm 13L
39x28x12cm
13L
30x25x13cm
linear: 68cm 8L
28x19x15cm
~8L
29x20x13cm
linear: 62cm 7L
20x15x8cm
linear: 43cm 2.5L