[EDIT: I thought you were looking to grow them, so these are to live nurseries. If you want cut flowers, you must contact local florists.]
It might be a bit early to get them...from what I can see, places don't ship until late winter at the earliest. Most prefer spring. You could always do a "IOU" thing. We did that for my mom once. She really wanted a particular variety of hydrangea that we couldn't get until April. She was still happy.
eWaterLily.com
Unable to ship lotus tubers until March
TexasWaterLillies.com
Actually, I think they might be shipping now, but I wouldn't be surprised if they don't.
PerrysWaterGarden.com
Again, they don't ship until March/April. But I like their selection the best. Very pretty!