Shweeash Bamboo is run by a jovial fellow named Dave. He definitely knows his bamboo and how to keep it healthy - I received 5 excellent specimens (phyllostachys aureosulcata spectabilis) from his company.
His prices are also the most reasonable you're going to find for bamboo anywhere.
Dave also answered the questions I had about my phyllostachys - even when I called a year later!
If I ever need more bamboo, I'm going to stay loyal to Shweeash.