Mostly this will be an FYI and not a recommendation as I think the motor you were suggested is probably just fine for the job. Later I will link to a company that produces custom wound motors that I really do like, but they do come at a price.
The motor's name is also an indication of it's size... but companies will use two different methods to name with... On the Leopard I believe they are using the outer dimensions of the case itself ( although I'm not sure where exactly they are getting the 55 from unless the diagram shown is the wrong one )... So the 5055 should be the outer dimensions of the "can" ... ie 50mm diameter width and somewhere they are measuring 55mm long.
The other method you'll see are the approx. measurements of the stator within the can. I prefer this later method since the thickness of the can material and the gap between the can and stator can vary, but that is still a subjective opinion. Either way, just pay attention to which measurement style the model you are looking at is using when comparing different motors.
The company I mentioned, uses the stator size to name their motors. Their closest equivalent to the one you mentioned is going to be something in their DM-4315 class of motors. The company name is Subsonic LLC and they sell Motrofly motors that are as mentioned, custom wound in a variety of kv's. In fact, you can call them and even get a motor wound to your own specs if you wish. The DM-4315 series has 16 available kv's to select from once you are adding them to your cart, their example spec sheet only lists about 6-8 examples of what you can expect out of a motor given a certain kv, voltage and prop size.
You can find them here
https://subsonicplanes.com/Home_Page.html ... They also welcome calls or emails for any questions you may have.