GameStop has revealed the box design for Mega Man Zero Collection on its preorder page. It features a commanding shot of Zero with Copy X embedded in the Z-Sabre's blade while Ciel looks onwards. All in all, it's pretty much the same design as the Japanese package, which is by no means a bad thing.
GameStop's pre-order page also says the game will ship June 8th for $29.99, as does Amazon. Uncertain if the date is official, so it's likely tentative for the time being.
Thanks for the tips, Sarge.