In article ,
(Dave Wallis) wrote:

I have just discovered that the Deardorff I was going to buy has a
minimum bellows extension of 7 inches, [...]

Are you really concerned with making the pictures properly, or are you
just having fun messing with spendy cameras? If all you are doing is flat
copy work, then place the camera so that it's in the middle of the
painting and parallel. No perspective adjustments are neccessary. Any
stout camera, even a silly 4.5 Printex, will do very, very well. Spend the
money on the _correct_ lens for the distances you are working with. There
are some excellent copy-work lenses. IMHO you are fretting over silly
things - for your application.