I'm curious as to the presence of horn literature that goes above a concert F at the top of the treble clef... the only excerpt I've seen is from Haydn's 31st symphony that goes to a concert F# (http://hornexcerpts.org/excerpt_pages/haydnS31/haydnS31_5.html) on a horn in D (a written high E). What other examples are there?
Ah yes, the Konzertstuck for 4 Horns. We just did a Horn choir arrangement for 12 horns of this over the summer.
I once saw a high F written, but I do not think it was by any well known composer. B's are common for all four horn positions. Everyone should have a high C, and if you are 1st you should have control of the D and E (which means you should be able to hit high G in practice I would say).
Since I play horn, I don't mind writing high notes for horns. If I can't play it, I don't write it. I have yet to write a high written F (above the stave) for horn, but I can play it, and I can almost play double C. That really high F is the same as high C on a trumpet, and since I can manage a higher G on trumpet, high horn notes are nothing to me. In my own music, I haven't exceed high C, but I have included a ton of high A's to C's.