Lots of cases already available for the BlackBerry Z10 from different companies. Incipio actually has some in girly shades. Currently, they only have the feather snap on case. But there are other ones listed on the main page for BlackBerry Z10 and they will be coming soon.
How the case is described:
Ultra thin form factor adds protection without the bulk
Easy and secure snap on installation
Soft touch finish for comfortable grip
It comes in black, blue, green and pink. The other cases feather SHINE, DualPro, DualPro SHINE and OVRMLD will be available later this week.
feather sells for $24.99 and you can order it from here.