I'm wondering if anyone has ever developed a trapeze for acoustic guitar that included features that would allow intonation adjustments similar to what is available on electrics? I have an old Yamaha Acoustic with a bellied up bridge that I might be able to make playable again if I put a trapeze on it instead of the string pins in the bridge. I'm thinking the trapeze would need to include some sort of floating adjustable bridge.
Generally a trapeze tailpiece is found on an archtop guitar and I'm guessing your Yamaha might be a flat top.
There are a couple of things to take into consideration with a tailpiece floating bridge arrangement that might make it a bad choice for a flat top guitar.
First, the breakover angle of the strings as they pass over the bridge might not be sharp enough with the geometry of a flat top guitar to put enough downward pressure on the bridge to hold it in place. You might succeed if you raise the height of the bridge enough but then the action might be more like what you see on a Resonator Guitar and it might not be very playable without a slide.
Secondly, a floating bridge may not vibrate the soundboard (guitar top) as much as the bridge and saddle system that came with the guitar which inherently is designed to impart maximum vibration from strings to soundboard. Archtop acoustic guitars that commonly feature a trapeze tailpiece and floating bridge usually have a top that is thinner with less rigid bracing that a flat top. Your Yamaha's top is likely too rigid given the thickness of the top and the bracing pattern to be responsive enough with a floating bridge.
Trapeze tailpieces with floating bridge are more often found on electric guitars which don't require that the strings transfer as much vibration to the soundboard since the vibration of the strings is amplified using the electronics and amplifier.
It's possible that if you did go with a floating bridge on your acoustic yamaha, you might need to install a pickup and plug in to get adequate sound. Otherwise it might end up sounding like a semi-hollow body electric guitar played acoustically.
I think the above may be the reasons we don't see adjustable intonation type bridges on acoustic flat top guitars. If you do try it, please let us know how it works out.