One 4096^2 is 64 512^2 textures. One 512^2 texture is already bigger than most peoples horizontal screen resolution for a mobile game. That's perfect if you are using them for some environments tile-ables. Are you really limited by the number of texture draw calls you can have? Time to bust out the texture atlas?
6x4096? Plenty of texture to work with if you divide it up :] I like choco's way of mapping a face to portion of the texture, I wouldn't duplicate it around though, I'd just work with my low poly surface and then do a planar projection, select all edges and cut them so each face is seperate and then snap align them…