Yer, I've been looking and the smallest I could find was 15cm in length.
I found one from Enermax, but I can't see any dimensions, it just looks smaller.
and it has to be modular as it's going in a very small case.
EDIT: I'm blind
Dimensions (W x H x D): 150mm x 85mm x 140mm
If I could get smaller it would be better but I doubt I'll get any smaller.