As far as I am aware I don't think a Carp / Bream hybrid is actually possible.
Deff get a Roach / Bream hybrid.
Also with the Carp family there are so many hybrids:
F1s - Crucian and Common carp
Fan TaiL Crucian - Crucian and Goldfish
Ghost Carp - Carp and Koi
Sure there are many more too?
One thing that is a real shame is I very much doubt there are any true 'wild carp' left, long lean bodies and always common carp. I think I actually caught some wildies many many years ago from a lake in surrey, now long gone tho