Do a search for "Terry Downs". Mr. Downs did a highly documented relief job on a Telecaster about 10 years ago and nobody that saw the results doubted they were correct and also everyone was disappointed by how little mass could be eliminated this way. Not worth it.
If you're thinking of this only to reduce weight, I would ask "why?". And suggest that regardless of the answer, it's probably not the best idea.
If it is because you want or need a lighter guitar for a physical reason (neck/shoulder problems), then I would propose that 1) you won't remove much weight this way, especially as offset against the amount of work involved, and 2) you'd be miles ahead just getting a different instrument.
If, OTOH, it's because you feel that lighter guitars sound better/different, I would suggest that you've misidentified the reason. It's the properties of the less-dense wood that's responsible...not the relative amount of it. I remember a while back people on the TDP were all about removing the neck pickup on Teles...not because of magnetic fields, but because it reduced the weight. I was thinking they should just insert tubes of helium instead.