Where you can sell bamboo depends on the markets you are interested in selling too.
There are many small local/regional markets available to growers for commodities such as shoots, poles, and live plants. Farmer's markets in urban areas are particularly good for this type of exchange.
Currently there are no domestic markets that I am aware of which handle large scale exchanges of raw bamboo material. That being said there are a few companies, small and large, and many individuals that are currently focusing their efforts and capital on creating large domestically supplied markets for bamboo. Alabama is currently ground zero for a few industrial scale R&D projects which may or may not pan out. If they do, say in the next 5-10 years, then farming large tracts of bamboo may be an option that may be available to you if you are growing the correct species. Proximity to future processing facilities will also be an important determining factor in whether the markets will be an option to any given individual grower.
If you want to stay in the loop on developments within these markets, and want to network with individuals and companies pursuing large scale domestic markets, you should join the American Bamboo Society
and the Southeast Chapter
if you are not already a member.