Seiko SUMO fans should check out SZSC004 at Rakuten. Some sellers do ship overseas. This model only available at on-line stores, not found at Yodobashi or Bic Camera. Last I checked, stocks still available.
As for those shopping for watches when travelling in Japan, Yodobashi and Bic Camera prices are usually 20 to 30% off the MRSP and if you bring your passport and paying by credit card, you will get another 5 to 7% discount off the non-GST price. Yes, you do not need to pay Japan GST. Bic Camera requires you to show a discount voucher (on line voucher also applicable) to get the full 7% discount, ask the sales person how to get the voucher (they are usually very helpful). Otherwise just take the 5% discount.