Recently switched out my t2i for a 50d as my 1.6 crop. AFMA and multiple f/2.8 cross type sensors have spoiled me with the 1dIII and now 50d. I love ML but do not see myself using the RAW video feature at all. Yes the prices have come up, but what the RAW video addon has done is brought out a lot of very lightly used 50ds into the market. Mine came to me with a shutter count of 4147.
XXXd vs XXd? Since she likes the feel of the XXd, I think that is the way to go. It is the progression pathway that Canon has spent years developing, mostly through selective feature addtion/removal. Even so, the more superficial things like better sounding shutter, top lcd screen, making her feel profession still count for the overall experience. Sure those thing have no effect on the photo itself, but there is also the enjoyment and just the mental factor of taking pictures. If she feels better and happier with a XXd and might feel more self conscious, less worthy, have regrets with an XXXd, regardless of the validity, it may make a difference in terms of, for example, her wanting to improve in new ways vs just doing what she has been doing or even losing interest.
Shutter count life expectancy is an estimate, but given her SPD (shots per day), XXd also makes more sense.
50d vs 60d. I didnt have to think about this. I no longer have a current 18MP crop sensor camera, but am ok with losing 3MP, a generation of DIGIC, losing maybe a stop of noise, worse screen, less advanced features all for AFMA. At least to me, it is that important. Shallow DOF and missing the plane of focus due to front or rear focus irks me and there is a lot of variability of lenses and camera combinations even within my collection.
One factor for you might be used market with 50d vs refurbished/new with warranty 60d. If your 50d needs a repair the first year, you could lose out in terms of money saved buying used vs having it covered with the 60d.
You mention low light in your first post. 60d or in my case t2i wins, slightly. More so in the noise deptartment per iso. I would guess less than a stop.
No matter what you get, its going to be an upgrade for her. Just dont forget, happy wife...