I recently did a crack repair on a Takamine EN10 (moral of the story: if you’re flying Turkish Air, don’t check your guitar) and I posted photos of the process in the Gallery.
There were two long cracks along the lower bout of the soundboard that had separated from the braces underneath. I used hide glue and a variety of clamps including rare earth magnets to create a seamless repair. You can still see the crack, but it came together nicely. I also placed a few cleats in strategic areas (where there were no braces) in order to reinforce the stability of the sound board. I did not have the time/facility to do a complete refinish on the front of the guitar, but I did as much as I could without sanding through the original finish.