[Ginger]

ben,
you are wise to be concerned about a shop putting her on a bike based on her leg length. They generally then stick a very short stem on the bike and call it good, and that short stem causes handling issues. Yes. The bike might "fit" but its handling is compromised.

I do have a suggestion. She's the only one who can protect herself from getting a bike that doesn't really fit. But you can help...tell her that while she'll be in a different position on a road bike, she shouldn't be leaning forward on soft tissue. And that's the key...if she comes across a fitter who tells her that some pain up front is "normal" they're wrong. There's a difference between a bit of pressure and leaning on the soft tissue.

Custom sounds scary, but it's the best thing I ever did for myself. While I'm not as tall as your girlfriend, I have a similar leg length/height thing going on.
If she really has no clue, start with a fit with a good Serotta fitter in your area. It will get you in the ballpark of what bikes will work for her.

And really, a custom cures a lot of expense down the road. No buying more saddles to fine "the one" when it just isn't going to happen, no buying different seatposts, stems, and handlebars trying to get all that dialed in.

For those of us who don't fit in the Nth percentile that most bike companies design for, custom is a cheap option.