As for what to expect with the figure, it will come with two changeable face plates, one changeable wrist part for his right arm and two for the left, a changeable left arm, and his trademark Bass Buster, which goes on the left arm. And as you know, he also comes with a figure of Treble, who is said to be quite large. Bass himself stands a full centimeter taller than the D-Arts Mega Man figure. Curiously, there is no mention of shot effect parts.
D-Arts Bass will be limited to online order via Premium Bandai and e-Capcom in Japan, and won't come to retail. Don't be concerned, however, since he should meet retail sale in the west. This was the same situation with D-Arts Vile.
D-Arts Bass goes on sale in Japan this June. Details on the North American release should come soon, too!
UPDATE: And as we said, Bluefin Tamashii Nations has announced the North American release! It will retail for $43.99 and is expected to come out June/July.