FWIW, just this December I got a new ST '01 model via ebay for 6,500 with bags and a two year warrantee. I would agree that you should be able to go to 6k or better.
I was also quoted 9k for a new '03 with bags.
However, a recent discussion on this forum
Used ST Discussion
Gave a link to an article listing the ST as a desirable used scoot and gave a price of 6k+ for one with bags.
YMMV,
Tom