I have one on order at the Pentax USA web store. When I called last week, they told they expected some units Sept 6.
I also priced one at
White Rabbit Express - Japan's top personal buying service and was quoted 387,500 yen if wired to Japan or US$5,187.74 if wired to their bank in the U.S. They would buy it from either Amazon.jp or Yodobashi Camera. Both have the lens in stock, so delivery would be one week.
I'm leaving for a two-week trip, so I'll wait and see if Pentax USA delivers. If not, I may buy one from either Japan or Taiwan (meanwhile I'll have to continue stitching verticals fro the 35mm)
Question to those who bought in Taiwan (or Japan): did you have to pay customs duties on arrival and how much? I will have to pay 8.75% CA sales tax to the Pentax web store, so I need to factor all the costs in the comparison.