$6,000 is probably doable, but not this late in the season I wouldn't think. In March or April, sure, but October?
Anyway, I know what you mean. I LOVE my ZX. It's everything I hoped it would be, but damn it's easy to get carried away with. I am 34 and I barely have the ability to contain myself on the street. It is simply too easy to go from 60 to 90 riding a long sweeper. And it's just as capable in the slow stuff as the Ninjette, at least on roads you know well.
Good luck selling it, or enjoy riding it if you don't.