Good question.

My limited knowledge is with Chapuis here, so my comments may have limited utitlity for Merkel and others. In short, if you buy a "standard" scoped DR from Chapuis, Merkel, etc. it will have the drop at comb for iron sights, NOT the scope. For example on my 9.3 Chapuis I had to add a leather comb raiser so the scope comes up "naturally" rather than me having to raise my head off the stock:

Now if you were to order a "made to measure" rifle from Chapuis or other makers they could make the stock fit for you with the scope that you asked them to mount on it. I know with Chapuis you can specify measurements of wood, and so this is theretically possible. But in all honesty in all the driven hunts I've been on in Europe where both O/U and SxS DRs are used often with types of holosights, most of the guys used similar comb raising devises so getting this done does not seem to be that common. Again, I could be wrong here.