I've just bought a gift for my Dad in a similar vein.
He had a little fender bender in a parking lot a week ago when he was trying to back into a parking space. A friend made the suggestion to me that we (my brother, nephews and/or I) might get him a back-up camera to install on his van. And she said her husband would be able to install it. Plus it was on sale for $70 off this weekend.
I thought it was a great idea. So I called my brother and nephews to see if they wanted to go in on it with me. When they called me back, my oldest nephew thought it was a great idea but was concerned that my Dad would be embarrassed by it, considering he's been a little upset about the whole incident. So they suggested that I ask him whether or not he would like one.
I talked to him and he thought it would be a good idea so I picked it up today!
So long story short... How much do you want this to be a surprise? If you aren't worried about the surprise aspect, just talk to her about it and see if it is something she might like.
Ummm... And I just read bloo's post. I agree.