I tune my guitar half step flat to make it easier to sing the songs I love to play. I also play harmonica along with guitar on many songs that feature a harmonica solo (Neil Young's "Heart of Gold" for example).
In standard tuning, Heart of Gold uses a G Major Diatonic harp. So it would stand to reason that I would need a G Flat harp to play the song a half step lower. However, when searching for a G Flat harp, I can't find any. What I have found is Major Diatonic harps in the key of F sharp - but with most Harmonica makers, that is the highest tuned Diatonic harp they offer and is too shrill for my taste.
I have found that Seydel and Lee Oskar offer a LOW F# Major Diatonic Harp which is basically a G Flat. But why don't they call it G Flat.
Every place I have looked online offers the following Major Diatonic Keys in their harmonicas: C, G, A, D, E, F, Bb, B, F#, Eb, Ab and Db.
So my question really is why is key of G flat, represented by F# and F is the only "sharp" key offered by Harmonica manufacturers.