That is a cool LB Action, one that I admit I had not used previously.
While this could somewhat be replicated using KM, I don't think it would be easy to get the nice list display and arrow navigation.
So, if you have not already done this, I'd suggest assigning a LB Abbreviation like "ST" for Safari Tabs. OK, it takes 3 keystrokes, but it goes fast for me.
I'm mostly a Chrome user, but I can't seem to find a "Chrome Tabs" LB Action. Do you know if one exists?