If you're an OF (or you've seen the reruns or bought the DVD), you probably remember the TV western (1958-61) called "Wanted: Dead or Alive" in which a young Steve McQueen (playing Josh Randall, bounty hunter) carried a sawed off 1892 Winchester .44-40 rifle in a belt holster:
The holster had an open design. With the right motion, it released very rapidly.
You can get something very close to that in a .44 Magnum lever action (or other calibers special ordered) from Wild West Guns:
Not enough? How about something in a .50 Alaskan in combat black with an underlug rail and an even shorter grip (which looks like the grips on very early black powder pistols)?
See more Bushwhacker options at the Wild West Guns [Anchorage, Alaska] site.
Looks like you need a Class 3 license and a stack of dough.
See the continuation for a discussion about full length lever actions
The Rifleman character Lucas McCain (played by Chuck Conners) also used Winchester lever-action, but it was full length (since the character was just a widowed rancher living with his boy). It was fitted with a large loop lever that enabled it to be spun and cocked in a dramatic fashion. The triggerguard
incorporated a screw that could be set to trip the trigger every time the lever was closed, thus firing the gun (or something to that effect). When the normally mild Lucas went ballistic, he didn't stop with one shot. When confronting multiple bad guys, he'd swing, aim, load, and fire off the hip, all in one smooth motion -- and never miss!
Want just a regular lever action in 500 S&W? Wild West Guns is more than willing to accomodate you (if you have the cash and you're not in a hurry). It even has the large loop ring lever like The Rifleman had.
A little something I found which might be of interest to you:
The "Mare’s Leg" (as he called it) used in Wanted: Dead or Alive was made by a gunsmith better known as a graphic artist, under the nom de plume of Von Dutch. A similar gun used in The Magnificent Seven was acquired by Long Mountain Outfitters when they bought out the inventory of a Hollywood Class III warehouse. It sold for several thousand dollars plus the $200 transfer tax.
Man! Would that be something to show your visitors!
Read more about it here (scroll down)