Thanks for the tip, I'll check out Kleen Kanteen and see if I can find one there. And yes, that bike is a custom bike by Vanilla Bicycles. I'm not sure if the bottle cage is custom or not. I would think so, as I haven't seen many designs like that, but it also seems like the bottle has a little lip half-way up that goes well with the cage in holding it.
If anyone else has seen this bottle/cage, feel free to chip in too please in case I don't find one at Kleen. Thanks guys !