Maybe you could say a little more about what you have in mind? What sort of guitar? Unless you plan to create a semi-hollow or hollow body from the solid (maybe like a Telecaster thinline?) the f-hole would not serve an acoustic purpose. This gets trickier if the top is curved, but assuming the top is flat you could do it with a router and template. I think the only way I have seen them on a solid body is where they go all the way through...as on the early Ampeg basses.

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That may also have some weight savings. You could do a purely cosmetic F-hole that does not go all the way through. If you don't go all the way through sanding inside the hole would likely be a bit of a pain...but it could be done ;-)