You have shown a great deal of ingenuity in making these belly guns. I do wonder though, if they are like that quote from Jeff Cooper. "An answer to a problem that does not exist!" A Belly Gun is obviously designed to be easily concealed, yet pack a big enough punch to instantly disable an armed antagonist! To do this, the weapon should fire a big enough and heavy enough projectile, at sufficient speed to disable a tough man. It has been known for years, that to effectively put a determined man down, needs a caliber of not less than .44, and a velocity of about 800 fps. Such a round will generate considerable recoil, so it is desirable that the pistol have a large enough grip to allow the shooter to maintain control of the pistol, in case follow up shots are needed to put your antagonist down. Now I observe that the pistol in Post #1, is based on a brass framed Remington, with a very short barrel. Even if the frame could stand the battering that a heavy load would produce, the muzzle blast from such a load, with the very short barrel would be very unsettling, even to a very experienced shooter! The other point is that with a grip of reduced size, the pistol would be more difficult to control for any subsequent shots, should they be needed!
I am a rather small man. I used to be 5'-8", but I am now 76 years of age, and I have the feeling that I have shrunk a little. I am probably 5'-7" now. I carry concealed an 1858 Remington Sheriff's Model. I do not have access to a Chronograph, and so I wrote to Duelkist1954, Who I know to be a Gun Writer for Guns of the Old West. I told him the load that I used, told him what gun I carried, and asked him what he thought my Muzzle velocity would be from a 5.5" barrel. He estimated that I was probably getting 950 fps. Now I happen to know the formula for determining muzzle energy, if you know the bullet weight and the velocity. So I worked out the Muzzle energy my pistol is most probably producing! it worked out at just over 282 Ft. Lbs. Quite respectable for a .44 Black Powder pistol!
I can very easily conceal either of my Remington Sheriff''s models. I use a modern Nylon Hunting Revolver holster, and not withstanding that I am a little guy, it conceals admirably under a short tan Safari vest. Now I have the advantage of the full grip, to enable me to hold the gun steady. the reasonably long sight base, (7 1/2") and the fact that I will be carrying the same gun that I practice with regularly! So therefore, I will be using the exact same gun I used almost every week. Like I said earlier, I am 5'-7", I weigh just about 164 lbs,( On the bathroom scales in the nude.) and my figure is justifiably called slim. Yet I can easily conceal a standard Remington Sheriff's Model. So why the need for a Belly Gun? My Sheriff's Models are standard, and I am totally familiar with them, as I shoot them most weeks, and am quite pleased with the results I get. Because the grips are full sized, I am able to get a firm grip on the gun, that I am FAMILIAR WITH! The barrel is long enough to give me a good sight picture, the barrel is long enough for me to develop a good muzzle velocity, and therefore a good muzzle ENERGY! In short, it gives a good bite to the fight!
The excellent (And now unhappily deceased!) Gun Writer, Elmer Keith, always said that the bigger the hole you punch in someone, the more likely you are to end the fight! I proved this in Australia while shooting Kangaroos. So instead of putting yourselves to all the trouble of messing around with a perfectly good gun, just carry a Sheriff's Model, and you will be well looked after.
I bought my Shoulder Holster from Cabela's when I got Betsina, my first gun. I bought the second gun just over six months later. Both are excellent guns, and I am well pleased with them both. I would agree that in a modern firearm, the Belly GUN can be shortened to advantage. In a modern cartridge gun, one can get some very interesting loads worked up, that will give good terminal ballistics, from a very short barrel. There are available very short barreled .357 Magnums, and if loaded with Glaser rounds, the 5 shot Smith & Wesson Chief's Special will give an excellent account of itself!
If you want a concealed weapon that has considerable Bite in the fight, and you are 5'-&" or over, you would be hard put to get a better one than an 1858 Remington with a 5.5 " barrel! it will do all you ask of it and more!