FWIW, in my experience the Japanese sellers, even with an offer option, are not willing to discount very much at all, usually only about $100 - $150, and that's for items in the 3k - 5k range. I agree with you that especially after only a short while they'd be less likely to.
Well, finally after trying for several days, I was able to complete the purchased for one in France. It wasn't easy at all. Their website has no translation and I had to jump through various procedural hoops. The good news is that the VAT tax is refundable, so in the end the bass will be about $3,200. I'll still owe shipping and an import fee, so I'll be back up to $3,700 or so, but that's much better that 5k for the Japanese one. Thanks to Macribas for turning me onto this one!