Why bother with a .30-06 case? The result would be seriously under length. But there is a simple solution:
It appears that the .270 WIN was originally devised by sizing down the neck of a .30-03 case.
So if you want to make .30.03 cartridges, simply get hold of some new .270 WIN cases and expand the neck!
If I had to do it I would take .270 WIN cases, anneal the necks, open them up with a .300 neck expander and then full-size in an ordinary .30-06 die that is set out the necessary 0.07".
For later resizing, find a washer of appropriate thickness (or turn one on a lathe) that supplies the extra length, so that you don't have to keep resetting the die if you use the .30-06 for making up .30-06 ammo. But .30-06 dies are cheap enough that I would buy an extra set for 30-03 use and label it !
Or simply fire-form, if you are experienced with that technique.