I'm figuring a light, takedown [breaks in half at the action hinge] over-and under with a long eye relief *scoutscope* mounted solidly on the upper barrel, with backup fixed sights probably zeroed for the bottom one- which may or may not coincide, depending on fortune, gunsmith's craft and whether or not it might be handy to have one regulated for 50 meters or so, and the other for about 150. The resulting package should fit neatly into lockable motorcycle saddlebags, including the teardrop *Enduro* bags of my old '65 BMW, which could handle a barrel or barrel/receiver length of no more than 21 inches.
The other swell little application I've considered is a 16 inch barrel in a Springfield M6 survival rifle, most usually encountered as a .410/.22 long rifle over-and-under, though the originals and at least some production civilian versions were in .22 Hornet. But I think the S&W .50 would be more useful around elk or moose, or, God forbid, Bear, for which something a bit more authoritative than a .410 slug seems prudent.
Hey, speaking of over-and-unders, wouldn't one of the little American Firearms or Bond derringers, sometimes chambered for rounds up to .45-70 be interesting in the new S&W .50 caliber? You could make folks wince just by showing them such a thing, once they'd fired the S&W dinosaur killer handgun, but with downloaded ammo, I don't think it'd be much worse than a .44 special.
-archy-/-