I haven't seen them anywhere, but I don't get out much...
In the meantime, you could try the Robert Lambert syrups that Surdyk's has in the bitters-and-Rose's-lime-juice aisle. The flavors are Blood Orange, Meyer Lemon, White Ginger, and Kefir Lime. I've tried the first two, so far, and they're quite nice. They are, however, made with corn syrup.
I'd love to try the Sonoma syrups - there's a great range of flavors and no corn syrup.