I was just thinking about starport bars and found this as a potential establishment:
http://www.archdaily.com/638009/bond-bar-hachem

nice floor plan and there are even 'spacey' images.  I'd envision this being a bit more upmarket than the usual dive.  I could even justify the name as a short "commonly known as" form of a bar named The Bonded Cargo or some such!
Lots of room for the traditional brawl, although I'd like to think that this kind of joint was above such things, and private booths for those all important trade deals.

For a more run down startown feel there's this:
https://quickandeasygames.wordpress.com/free-stuff/
which includes a (non-Traveller) scenario it would be easy to adapt.

Of course Brubek's is always an option (from GURPS Starports, p.87).
Or Hotspots 1: Drifter's Dock (from DSL Ironworks who also produced Quick Decks 6: Frontier Starports which has a potential bar in there somewhere).
Revelation Station (QLI) has The Crew's Lounge though it's a tad small for my purposes.

and I think I once had one on a real frontier planet that was just a converted modular cutter module opposite the 'scout base' (another module!).

Hope this helps

tc