I've used grommets on mandolins for well over 20 years, and it's pretty much a common practice in the mando world. I simply adapted it to guitars with trapeze or Bigsby tailpieces several years back... in fact, I'm pretty sure that I'm the one that brought it to this forum (inadvertently) way back in 2008-2009, when I posted pics of some of my guitars and somebody asked, "What the heck are those things behind the bridge?"
Of course, it's not an ideal solution, since you need to carry extras in case you break a string, because the grommet will sure as heck go flying off into parts unknown. Others don't care much for the aesthetics of the grommets...but it's cheap, effective, and they just work for me.
Most car spares stores. They're just rubber bulkhead grommets.
People look for similar 'solutions' for Jazzmasters, Jaguars and other similarly 'stricken' guitars, but for me, it's part of the character of the guitar, so I don't 'fret' over it. Same with three saddle Teles - there's ways to set them up that negate the intonation stuff.