Barranquilla is the only pure Colombian locality I ever see besides WC imports. The bloodline I see most frequently is the Rio Bravo mentioned above. This is the line Vin Russo at Cutting Edge Herps has and where I sourced my 2021 pair. Michael Beach at Woodcliff Herps also has very nice, yearly litters of this line and I think he supplied the ones to Brian Boas.
Daniel Palenque at Animalia has some very interesting Barranquilla color variants like charcoal, purple, and red.
My speculation is that Colombia localities aren't more popular because the generic "Colombian Boa" label gets slapped on any boa with an unknown heritage. This probably makes it hard for dealers to charge a premium or market a 100% pure Colombian Boa.
If you do the FB thing, there's a small group called Pure Colombian Boa Imperator you may be interested in.