Today is the release date for April Japanese items, so look out for your toys if you pre-ordered any of them... or start looking online for them if you hadn't.

Transformers Adventure
TAV13 - Nemesis Prime (black/aqua redeco RID Warrior Optimus) - April 25 (2,500yen)
TAV14 - Ultra Magnus (Beast Hunters VOY - darker redeco) - April 25 (4,300yen)

Transformers Easy Dynamic Series
TED06 - Big Optimus Prime (RID 3-step - darker redeco) - April 25 (3,600yen)

Q-Transformers
QT-18 - (Movie) Nemesis Prime (redeco Movie Optimus - Western Star 4900SB) - April 25 (was March 21) (1000yen)
QT-19 Gen1 Convoy - April 25 (1000yen)
QT-20 (??) Megatron (grey Lamborghini Veneno) - April 25 (1000yen)

Transformers Adventure EZ promo (with 3000y purchase)
Optimus Prime (translucent red & blue) - ToysRUs (April 25)