Another vote for 6.5x55, especially if you were leaning towards the .243
If you were leaning towards the higher end, then 7x57 or 7mm-08 would do good, but I don't know how much difference in recoil they would be compared to .308.
In any case, pay attention to the weight of the rifle too. If she insists on a light rifle for similar reasons, then a lightweight 7mm-08 may not be much difference in recoil than a heavier .308
If you were leaning towards the higher end, then 7x57 or 7mm-08 would do good, but I don't know how much difference in recoil they would be compared to .308.
In any case, pay attention to the weight of the rifle too. If she insists on a light rifle for similar reasons, then a lightweight 7mm-08 may not be much difference in recoil than a heavier .308