That DIY bridge is pretty cool. I guess different material would sound different too.
Thinking it might be possible to make individual saddle pieces for a TOM style bridge too. Then you could still intonate each string and adjust the angle of the buzz slope for each string.
The sympathetic strings are also pretty interesting. I had no idea sitars had them. The springs in my Ibanez with a FR bridge buzz like anything. You could maybe put strings in the spring cavity of a Strat or similar. Though I'm not sure what notes you'd tune them to.