Just adding my voice in support of this. When I only had a few cats, I thought it would be a bad idea, but now that I'm up to my prim limit I think it would be a terrific feature. I'm sure it could be made optional to preserve the surprise for those that like it.
I think it would help with the secondary market too, I know I've decided against buying boxes because I need a cat of a particular sex (usually boys - I have a crazy amount of girls). It might also help stop prices from falling, I know I've reduced prices just to try and get rid of some of the girls!
Anyway, fingers crossed we'll see this in an update soon.
On a side note, I'm totally addicted to these things, and the customer service is amazing. Thanks!