Think some of the holsters made by the better quality custom kydex guys are cool? How about a holster for a LAAW from S&S Precision? You will still need the sling, but at least it's not slapping your back flopping around while you're patrolling and climbing.
(Note: not really a holster. It's a retention device. Don't be so literal.)
Since not everyone has the opportunity to carry a LAAW around on a daily basis, perhaps this would suit you better. S&S "One Size Fits All"
![Turkish Foreign Minister Mevlut Cavusoglu (left, pictured November 2018) said after a phone call with U.S. Secretary of State Mike Pompeo that he finds "correct his statement about the removal [from Syria] of the elements that concern Turkey." (AFP photo/Nicholas Kamm)](http://images03.military.com/sites/default/files/styles/thumbnail_large/public/2019-01/turkish_foreign_minister_mevlut_cavusoglu_l_pictured_november_2018_said_after_a_phone_call_with_us_secretary_of_state_mike_pompeo_that_he_finds_correct_his_statement_about_the_removal_from_syria_of_the_elements_that_concern_turkey.jpeg.jpg?itok=fQLV2lTj "Turkish Foreign Minister Mevlut Cavusoglu (left, pictured November 2018) said after a phone call with U.S. Secretary of State Mike Pompeo that he finds \"correct his statement about the removal [from Syria] of the elements that concern Turkey.\" (AFP photo/Nicholas Kamm)")