If you have an interest on your own behalf, it might make more sense for you to resettle one of your old knives with her and buy yourself a new knife. [...] Talk to her about it.
Before breaking down the choices into individual lines, it would be helpful to know your price range, whether you prefer a "German" or "French" (which is also Japanese) profile (
link to a post describing the profiles in more detail), and how you plan to keep the knife sharp.
Unless you're willing to live with the mediocre F&F you find in student level Japanese knives, it's going to cost you north of a $100 for a 10" knife which beats a Forschner by enough to make it worthwhile.
Also, it's just a shame and a waste of money to buy an expensive knife you can't keep sharp. Not all sharpening methods work equally well for all people -- we need something with which you'll be comfortable. And, not all methods work equally well for all knives. If you don't already have your (and her) sharpening figured out, we should start there.
Like French vs German, 8" vs 10" comes down to personal taste. But just as French rewards good skills better and German punishes bad skills less, so with 10" and 8". Anyone can make a 10" handle as intuitively as an 8", but it does take practice which, in turn, takes a willingness to learn. It's not something you can expect your lady to do unless she wants to. And, even if you do most of the cooking over there, she should have a knife in her house that's comfortable for her.
That said, my Linda, who doesn't have trained skills and doesn't want to hear any crap from me about it either, took to my 10" French carbon like a duck to water while becoming a sharpness junkie at the same time. It took about 4 months until, "Honey, when are you going to sharpen 'my' knife?"
BDL