Well... I just went to Kobo to look at creating a US account to purchase Shogun. It looks like James Clavell's books were released to Australia in e-format in June of this year... That's what I get for not double-checking before creating a thread! I had last looked for Shogun in about May - only a month too soon!

However, Musashi, as recommended by Katsunami, is still locked firmly away from me. I may still look into creating a US account for that.