@Tubbz, mind if I ask why you want it to have a 17in screen? Since you could make the resolution slightly lower than the native one and it'll make things appear bigger, so she won't have to strain her eyes trying to see what's on the screen!! My friend's mom had some huge ass monitor and used something like 1280x800 so the text would be massive. Also, the centered touchpad thing won't be an issue if she uses a USB mouse :0 There are a lot of small and really lightweight ones if mice are normally too bulky and heavy for her or something
The "setup" she uses is basically the laptop lives on a table on wheels that she has pulled in front of her chair. There's not enough room for her to use a mouse as well.