Run a search for mahogany. You probably won't find a lot. That's weird, since it's a pretty common wood. My guess would be that it is just not good in its bending properties. Guitars are static objects where sound matters more than strength. I think, but this just some gut feeling without any fundamental experience, the wood has a low shear strength. It may not hold up as a core.
I like Mike's suggestion though; making a minibow will tell you a lot about the wood, especially when you test it till destruction.
I'm thinking bubinga, jatoba or cherry would be a better choice for cores, with a pretty similar color.