There is an announcement about a Pink Zune on EBgames which is "coming Zune". They claim  it will be available on 1st May! Is Pink a limited edition Zune which will become... unlimited edition ? EDIT: a comment from EBgames...

This pink Zune according to EBgames will have the same features with the already released Black, Brown and White colored. Everything will remain as we know it, this is not a new version. 

 See the announcement on EBgames . It has no other information, but ClicZune asked them and their answer was 1st Ma is the released date!

AbsoluteZune says the same Pink Zune will be available also from Gamestop. Check it here (the release date is also 1st May).

[via AbsoluteZune & ClicZune ]

EDIT4: Some baby Pink and Red Zune photos

EDIT3: and some weeks later the Watermelon Red Zune will be released.

EDIT2: And the official confirmation by Jason Reindorp

EDIT1: I sent an e-mail to EBgames asking about Pink Zune and this is their answer: "The manufacturer will begin producing these Pink Zunes for regular sale in the future. We do not have a date as to when we will begin selling them."