I did more research on MotoStorm and it seems like they get pretty good ratings, so I went ahead and placed my order. I ordered the Givi V47 top case with the backrest pad, mounting plate, and LED light kit all for right around $300. I placed my order yesterday afternoon (Sunday), and I got an email this morning that my order will ship today, with an expected delivery date of next Monday. I think that's pretty good. I also found out that the Kawasaki top case is made by Givi, and is identical to the V47.
I ordered the Kawasaki rear rack from my dealer though (for a discount since I just bought the bike there). I would like to rig up some kind of rack on the back to be able to carry my bicycle as well, and the OEM rack seems much more robust than the Givi one.
I'll post up pics when I get it all on the bike.