Far from a hive of scum and villany, 2001: A Space Odyssey's Clavius Base might well have been the first visual reference for Mos Eisley.
An interesting and easily overlooked piece of (potential) inspiration from 2001: A Space Odyssey, is Clavius Base (above in Robert McCall's art, and below in a still from the film) as seen from a nearby ridge with Heywood Floyd on approach in that thing that looks like the droids' escape pod from behind.
Similar in shape and layout, here's Ralph McQuarrie's earliest depiction of Mos Eisley as seen from a nearby bluff by a girl who would, from a certain point of view, go on to become Luke Skywalker.
Both settlements are largeish, low-set structures in a circular-like fashion, devoid of towers. Both are also space ports.
Interestingly, another space adventure also inspired by 2001: A Space Odyssey was the popular TV show Space 1999 (1975-77) — which famously caused the redesign of the ‘pirate ship’ due to the original design’s similarity to that show's primary ship, ‘The Eagle‘ — had its own base, named Moonbase Alpha, which also looked quite a lot like Clavious Base.
McQuarrie's painting, referred to in The Making of Star Wars as ‘Luke as Girl Overlooking Mos Eisley’ was finished circa April 1st, 1975 and Space 1999 didn't premiere until September 25th that year. So if McQuarrie indeed was inspired, would have been from Kubrick's classic.
Here's how it turned out in the final film.
And, as I was writing this post waiting for the trailer for The Force Awakens, it would only be fitting to note how it too featured another view from a ridge.