I had a Punto up until the end of December. It was a 9 year old car, but I'd only had it for 2 years, and up until last Easter I didn't have a single problem with it. As it was a 1.2 engine it was very economical to run - I used to get 45-47 mpg out of it and I have a lot of hills and roundabouts on my journey to work, so lots of clutch and gear work.
I would say that the boot on a Punto is probably one of the biggest boots going for a small car. It's also one of the roomiest cars I've been in considering it's small, so I don't think she'd have much difficulty getting a double buggy in (although I'm not that sure of the size of them!) and she'd definitely have no problem getting two baby seats in the back. I'm not sure whether the boots on the new models are quite as big, as they brought out the Grande Punto a few years ago which is still a small car, but with a bigger boot. Depending on what she wants to pay she might be better going for a Grande Punto with a 1.2 or 1.4 engine (I think they're about £7000-8000 for a 3 year old model or about £9500 for a new model).
I changed to a Suzuki swift as I got it at a bargain price, but I wouldn't hesitate to go for a Punto again! xx