The first rhizomes i bought from ebay - very few came up and they all died, but to be fair to the seller, i didn't know much about what i was doing and i think now i might could have better success.
But if you crunch the numbers, even with good care, you will be better buying potted plants.
I ordered 2 orders this fall from BambooGardenCenter.com 8 plants each time and i thought i got some good deals buying 16 plants on sale for 11.99 each plus shipping.
They didn't have madake on sale, but i think it's regular 20.00 and i have my own madake grove.
I bought some Rubromarginata and had enough wild rhizomes sticking out of drain holes to pot up into 5 or 6 new pots with shoots growing fine from the new pots after planting out the original.
I bought some nice Phyllostachys viridis 'Robert Young' for 11.99 and Phyllostachys bambusoides 'Castillon' for the same price and i see they still have some. Plus they have a black Friday special.
By the way, BambooGardenCenter is the newer version of BambooPlantation.com and there's lots of good info there as well.
You being on the west coast, i recently ordered some Japanese maples that were real nice from a seller out your way, and i see they have bamboo too. I actually e-met the owner and he seems like a real fine guy. He's nearer your location and his place is
http://japanesemaplesandevergreens.com/I have my greenhouse rather full, but it's always tempting to buy a few more plants.
I guess i need to start thinking about building on to the greenhouse.
Hope it helps!