Uh, when it first came out for PC it had a collector's edition box too, plus a digital collector's edition.
The collector's edition coming in April is for the 360. The edition, which, you know, is a fair bonus for those of us who had no PC and had to wait nearly a year to play TW2.
CDPR is an incredibly small company. I'm not going to pretend I know anything about programming, but from what I've heard from several sources, it's a lot easier to port a PC game to 360 than it is to PS3. I highly doubt they had the resources to work on a PS3 version at the same time. I believe they haven't officially ruled out doing a PS3 port, but we'd have to wait a while just like we did for the 360 version.