"Current designs have a latch on the top strap. That doesn't mean that is the only way to hold the action closed. I'm not talking about having a latch on the cylinder. I'm talking about having the entire latch mechanism located below the cylinder."
JSH1,
Though it is fairly low on my list of project priorities (mostly because each and every part of a revolver is kind of a pain in the rear to visualize and make), I am working towards this exact concept for my "Stampede*" design. The design a forked "upper" receiver that hinges about the chamber like a cannon trunnion and locks into seats on either side of the trigger area. The only reason the latch is as beefy as I have it is to allow the user to safely slap the thing open and closed (we all know we wish we could do this without jacking up the guns). The latch does not carry significant load (mainly just resists the torque of recoil). The attached image is based on my 44mag Blackhawk Parts kit, which is the planned source of barrel, cylinder, etc. (I also have a GP100 kit that may work if 44mag proves too stout an undertaking, but I have it slated for a further evolution of this idea; breaktop autorevolver). Blackhawk parts aside, it's still a big 'ol hawgleg, but it's nearly Dragoon sized in this current incarnation.
Comically enough, I do not feel the reason these guns are unpopular for new offerings is due to design, demand, or engineering. For a modern cartridge of any power to be contained, the
hinge and its attached frame, not necessarily the latch, must be pretty beefy. It rapidly gets worse as the bore axis height increases, like with a Webley. The real solution is a bottom-firing layout, but this design option quite simply
cannot be made to look presentable. The void above the barrel is substantial, and sighting offset concerns aside, a designer is practically forced to "fill in" the area with needless bulk to appease the eye.
This link is to an earlier sketch I made
trying to come up with an aesthetically 'pleasing' (in the old-school Fudd sense, not the cyber-punk Rhino sense) concept. Even turning the ejector rod housing into an "over lug", you still need a 1/2" or so rib sitting on top get the lines right. One nice benefit, is that the sight height can be in line with the top of the cylinder, so overall height is reduced by 1/4" or so. A lot of people say the Rhino would sell better with more classical aesthetics; it quite simply cannot be done, and the present design is about as pretty looking as you're likely to get. The "flow" of the fat grip to tapered muzzle does not work unless the barrel is high up (which is why the Rhino tapers from fat muzzle to narrow grip). My 'solution' for my "Stampede" concept is to mount a laser or "periscoped" red dot in a hollow tube squatting over the ejector rod housing, that way the added bulk won't be completely useless**.
TCB
*yes, it's a veiled reference to Trigun
**yes, this is why Vash's revolver had this exact same design feature (slash plot device) seated over the barrel --it looked really stupid without it