Sitar bridge mod (for floating-tailpiece guitars) idea
My guitar has a "floating tailpiece" as I believe it's called, in which the strings pass beyond the bridge to the tailpiece. The segment of the strings below the bridge have no part in tone generation, and so could have an object attached to them (a piece of wood wedged between the strings, perhaps) without affecting the guitar's tone.
If some object (the "clamp") were attached to the strings immediately below the bridge, another object (the "sitar bridge") could be affixed to it some minuscule distance from the vibrating portion of the strings. The sitar bridge would not make contact with the strings at rest, and so would not be a node of vibration (and not affect the strings' pitch), but when the strings are played, their vibrations would make them rattle against the sitar bridge - much like the bridge of an actual sitar.
So how about it? I think it'd be an interesting and relatively simple mod that could be made to be removable and not destructive at all to the actual guitar. I unfortunately have no idea how to refine the concept any further than what's written, so I leave it up to any willing DIY-ers. It all makes sense in my head, but I may have accidentally left out some important particulars of this kind of mod, so please ask any questions you have.
Because this mod relies on the strings below the bridge in a floating tailpiece guitar, I don't think it would work on most solid-bodied guitars, but if anyone can come up with a similar mod for the more common bridge type, be my guest. Also remember that the "clamp" below the bridge cannot rely on the tensile strength of the strings, as not only are they not terribly strong, their tension needs to remain intact so that the guitar can be played in tune.