Suffice to say if one does this at home it will be easier to evaluate.
Glad you were fortunate enough to have a well adjusted scanner! I was not. I had to raise the holder significantly to get the scans sharp.
I think the bottom line for large format film is that even out of the box with OEM holders, the v700 is good enough for 4x5 and above. The scan ppi requirement is so low one just doesn't stress the capability of the scanner. It is only if you will also scan smaller formats (as I do regularly) that you will really appreciate the improvements of the 750 and the betterscanning holders.
I am here: http://maps.google.com/maps?ll=40.029159,116.510979