Here in Texas we are maple-poor, but oak rich - a vastly underused group. We have about 40 native Texas oak species, none of which are used very often in bonsai. The southern live oak is a really great tree and responds to bonsai culture very well. But there are amazingly few in cultivation. As for the rest of the oaks? I've seen a couple of red oaks, white oaks, willow oaks and water oaks. They also adapt well to bonsai culture. I've seen none of the rest and some of them are fantastic deciduous species with small leaves and great fall color. Why don't we seen any of them? California is way ahead of the rest of the country using their oaks - I've seen fantastic specimens of Coast Live Oak and Golden Cup Oak produced. But there are many oaks of similar quality elsewhere in the country. I honestly think that if bonsai had been developed in the US, oaks would be king and people in Japan would be trying to figure out how to make their local maples look as good as all of the fantastic American oaks.
If I could quadruple like this post I would. I completely agree. Unfortunately, people here have ignored Eastern and Southern oak species or assumed they're unbonsaiable, or start off with crummy saplings that never amount to much.
Live oak and its subspecies make spectacular, tough, easily trained bonsai. Willow oak too. Both are every bit as bonsaiable as California oak. I know Don Blackmond has some massive and amazing White Oak bonsai--or had. Don't know if he sold them.
Texas alone has a forehead-smacking 42 species of oaks, about half the total number of oak species in the US. Twenty nine of those species are termed "dwarf," "small" or "medium" sized between 15-50 feet in maturity. I've had one of the "medium" sized species, quercus fusiformis as a bonsai for over 20 years. It is just under three feet tall with small leaves. If that's how a "medium" sized species behaves as bonsai, can't imagine how the small and dwarf varieties would work out. FWIW, the picture is just a snapshot I picked up off an East Texas real estate page. Typical landscape, all the trees in it
are oaks of varying species.