What lens for the GX1 or must be 12-35mm and nothing else?

I am tracking the GX1 at B&H ($319) but having gotten use to the LX7's bright lens, I don't want to be shelving the GX1 with kit lens for the LX7, but want a compliment. I need some zoom and the LX7's range is almost perfect for me (given my penchant for WA shots), so I'm seeing only the 12-35 as getting me to where I want to be, and I'm up to gulp $1,400. That's a lot when I've got a 60D with three lenses sitting in the bag. Is there any other lens that will get me low light IQ and is stabilized?

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