Apparently they are not just for Bandai's Hobby Museum, but are available through pre-order from Bandai Premium as well, but they are limited items nonetheless.
MG Gundam Mk. II Tokugawa Ieyasu Ver.
* Represents Tokugawa Ieyasu in armors he worn in his first battle.
* Has a new "Serenity" style sticker included.
* Body armor parts are plated.
* Has new helmet design.
Pre-order period is between July 23rd and August 27th. Late September release, 7,000 Yen (inclusive of tax).
BB Senshi Tokugawa Ieyasu Gundam Black Armor Ver.
* Designed based on Tokugawa Ieyasu's victorious image at the Battle of Sekigahara (関ヶ原の戦).
Pre-order period is between July 23rd and August 27th. Late September release, 1,300 Yen (inclusive of tax).
Images are from Bandai Premium: MG Gundam Mk. II Tokugawa Ieyasu Ver., BB Senshi Tokugawa Ieyasu Gundam Black Armor Ver.