The first thing that popped into my head was Claire. I think Fiona Rose is too many "o" sounds. Nothing wrong with it, but not quite as pretty as some other combos, plus Rose is kind of a filler middle name (though pretty).
Have you tried the nymbler site? It's great fun and might help. www.nymbler.com
Fiona would also go well with a longer name too, if you were inclined.
Here are some others that are a little different, maybe. No clue if you'd like them or not.
I really like Fiona. It's a quirky, fun name.