These tropical hardwoods can be very beautiful - if you can care for them in the (mostly) cold US.
True mahogany (Swietenia mahagoni) is a Florida native, but most people wouldn't know it if it bit them in the butt
We've had other discussion about this on the site, but the vast majority of "mahagony" wood you see for sale isn't even in the mahagony genus. True mahagony hasn't been harvested since 1950 (most of it came from Cuba) and big leaf mahagony (a closely related species) has been on the endangered species list since 2003. If you see any furniture that someone claims is made from mahagony and it isn't at least 70 years old, be extremely skeptical.
Another interesting American native is Texas ebony, which has a very interesting hexagonal growth pattern that reminds me of organic chemistry
I believe Texas ebony has the third hardest wood in North America, just behind desert ironwood (which isn't a true ironwood).
The tree with the hardest wood in the US is black ironwood - another Florida native. Generally speaking, the tree is too small to be commercially harvested for lumber... except for smaller projects.
I have a Texas ebony, and I think it is suitable for bonsai due to the interesting growth habit and small leaves. I don't know about black ironwood... and desert ironwood is from the Sonoran desert and is more of a desert shrub than anything.