If nothing else can be said, Fujifilm is always very quick to reply to my enquiries which are surely written in the worst Japanese they have ever read... no, not google translated, I write it myself but surely school children could do better. Their reply, trying to politely point out an old press release from September of 2009 when production stoppage was announced:

フジフイルムモールサポートデスクです。
平素は弊社製品をご愛顧いただきありがとうございます。

大変恐縮ですが、ご指摘いただきましたとおり、「FP-100B」は
2009年6月をもって、製造終了となっております。

現在は在庫のみの販売とさせていただいており、売切れ次第
終了となります。

・インスタント黒白FPフィルム一部製品販売終了のお知らせ
< http://fujifilm.jp/information/articlead_0018.html >

せっかくご利用をいただいておりましたところを、大変申し訳
ございません。
ご要望にお答えできず恐縮ですが、何卒、ご了承いただけますよう
お願い申し上げます。

担当:磯村

So there you have it though if you follow the link to the article I think they made a small typo in the reply to me on when FP-100B ceased production:
弊社最終出荷時期:FP-400B/504Bは平成22年3月頃、FP-100B/104Bは同年6月頃。

The article says that FP-400B/504B ceased production in the year of Emperor Heisei 22 March while FP-100B/104B ceased in the same year in June. Unless I'm mistaken, Heisei 22 was last year, 2010, not 2009 as in the reply they wrote to me. Ah well, at any rate it really did cease production almost a year ago sadly so all they have left now is existing stock. Smoke 'em if you got 'em...

As of that old press release, FP-100C and FP-3000B production continues. At least they didn't tell me that anything else has been discontinued though scarily they say the link to the article about the end of the black and white pack film products... hopefully that doesn't mean the writing is on the wall for FP-3000B as well.