I see the kinect v2 is available for pre order, and will be available in about 3 weeks.

I was considering buying 1, but not 2 at this moment...

Will it be possible to combine 1 v2 with a v1 kinect?

Initially - surely not. They differ much in hardware parameters - FOV, resolution of depth and color.
We may think of this possibility later. But I suppose it won't be a worthy option once Kinect 2 is generally available.