It turns out that it's too much cost for a Yam box, or more than I want to pay, as I don't have the Yamaha rack/mount. I do however have a Givi Monokey mount so still could be interested in a Givi (Trekker) box if anyone has one ?
I've got a Holan from Poland and really like it. For you, their new prices are not much more than a used box, and shipping won't be as much as for us in the US. This is only 150 Euros and other sizes are available.