Stick,
In all honesty, about all you can do is mention it once-in-a-while here on the forum when the conversation favors such a comment or write a suggestion letter to Buck. I have pushed, using personal contact at knife shows, etc., for a two blade 303 an 301 with a regular clip blade and full length sheepsfoot or warcliff blade, for several years. I even had a couple of custom versions made up and sent them in to the high ups at Buck and no luck or even comment. So all I can say to you, Best of Luck with your ideas. I do think for a bottle opener to fit comfortably in the hand when closed and not in use you would have to have a large body knife, maybe a 301 or bigger. Take a bottle opener bladed knife and trace the blade on a piece of paper, cut it out, and see how it looks slipped down in the blade well of a 303 or other knife. I think designers would tell you the can and bottle opener blades have seen their era pass. You might get somewhere if you were wanting a blade to work on a I-phone or x-box.
I even pestered the BCCI board enough to offer a special order 300 knife, and the board finally gave it a go when Buck came up with enough metal to make 200 BG-42 bladed 301s, and we couldn't even get the 2500+ members to buy 200 of those. Not a very good 300 series impression for Buck to view. I believe I will give up and just let the 300s be what they are, knives for the pocket. Something to cut straps and string, sacks and plastic wrap. If you want a fancy one you will just have to customize it yourself.