1) A few years ago, 3 cases existed that were being made. Now, you'd have to find one used. Digilog made 2 of them.
2) Can't help here
3) Realforce is the official brand for boards made by Topre, and uses typical Topre switches. The Novatouch uses a modified Topre MX-compatible slider. The often voiced concern with the Novatouch is that it doesn't provide the tactile feel and sound typically associated with a Topre switch. Some will argue with some necessary modifications, it will come close.
4) If you are referring to the variable board, then yes. Otherwise, Mechanicalkeyboards is selling "Ducky Taiwan" editions of Realforce boards in all 30G and all 45G currently. They are silenced versions. Beyond this, you may need to review the Japanese market for more options, but keep in mind those are primarily JIS boards.