Digital BW, The Print

Does anyone know where I can take a look at key performance stats for several digital 
cameras?  I am keen to compare the Canon 1Ds and 1D MK II against Leaf and PhaseOne 
digital backs.  I know these are completely different solutions but a I struggle with 
understanding the price gap.  If one extrapolates the 1D MK II pixel count up to a full 
frame 35mm hopefully-to-be-announced-in-the-not-so-distant-future 1Ds MK II then it 
could be around 16-17 megapixels which really becomes very interesting.  I understand 
the Canon is 12 bit vs 16 bit for the higher order digital backs (but then not so long ago 
we did almost everything in 8 bit.....).  So I assume the signal to noise ratio is where the 
battle is.  (I can process the RAW data of either a Canon or PhaseOne in CaptureOne and 
so that is an even platform.)  I just took a look at the portrait shots on Canon's website 
from the 1Ds and did not think these were particularly sharp vs shots from a 6mp 
PhaseOne back I have used.  What other key factors should I be looking at?  (please ignore 
portability, handling ease, fps etc  -  just image quality.)

Thanks

Steve