Reading through even more revues and the information posted above, here's what I've found the current region 1 Toho Showa Daikaiju to date. These titles are currently available:

Classic Media (Japanese w/ English subtitle version and US cut and dubbing) - boxed set of Godzilla, Raids Again, Mothra Vs, Ghidorah, Monster Zero, All Monsters Attack/Revenge, Terror of Mecha, 2 disc set of War of Gargantuas and Rodan

Tristar/Sony (Japanese cut w/ English subtitles or international English Dub) - Mothra (with H-man and Battle in Outer Space), 3 pack of Son Of and Vs Mecha (packed with SOS Tokyo too)

Universal (US edit and dubs only) - King Kong Vs and King Kong Escapes

Tokyo Shock/Media Blasters (Japanese w/ English Subtitle or international English Dub) - Dogora, Frankenstein Conquors the World (also includes US edit and dub)

Criterion - Godzilla Bluray


The following are out of print at the moment, but maybe they will be back out or in Bluray with the new Godzilla next year:
Tristar Sony (Japanese cut w/ English subtitles or international English dub) - Vs Ebirah, Vs Hedorah, Vs Gigan

Tokyo Shock/Media Blasters (Japanese w/ English subtitles or international English dub) - The Mysterians, Varan (Japanese cut w/ subtitles only), Atragon, Destroy All Monsters (DVD & Bluray), Yog/Space Amoeba, Vs Megalon bluray? (it's up for preorder on Amazon)