Upgrading Graphics Card by Replacing Logic Board.

I'm fully aware of the fact that the graphics card for a Macbook is soldered into the logic board and as such can not be replaced by itself. However, I've read online that it is possible to update the card by replacing the logic board itself.

Is this actually possible, and assuming that this is possible, will I be able to use a logic board from a later generation, or will I have to stick to one from my MacBooks generation (late 2009)?

Finally, if this is possible, is it even a good idea?