Public domain, Creative Commons etc. musci sources wanted

My latest film project is in the style of a fantasy epic- think LotR, Narnia, that sort of "party of brave adventurers battle evil in a non-specific setting resembling mediaeval Europe" thing. It's in post-production now, but while we are ok for visual effects and editing we really need some music. To keep options open regarding public performances, we make sure to use music that doesn't infringe any copyrights- the last film only used original compositions and public-domain soundtracks.

For this film we need public-domain music in a fantasy genre. The links below illustrate the sort of style we are looking for. Public domain recordings would be great, but freely-reproducible scores would be ok as we have a couple of talented musicians in the group who can play pieces with limited instrumentation, but sadly no full orchestra!

The best answer will receive a Best Answer, probably a patch if the answer leads to some good sources, and possibly (at the discretion of The Powers That Be) a credit in the film.

Rousing orchestral music
Sadly we have little hope of reproducing music like this, but any public domain not-too-recognisable pieces would be absolutely great.

Celtic-sounding flute/whistle music
... is something we could actually play. Recordings would be better, though.

Faux-mediaeval strings
Oh, what I'd give to have a cellist on board. Oh well.

Slow reflective piano melodies
Not quite as "folk" as the rest but would give great colour to the sad moments in the film

Harp music
No, we aren't going to rip off the Braid soundtrack. I know, it's a shame. The only harpist I know is busy studying for her veterinary medicine degree so doesn't have time for our stupid projects.

Of course, if anyone plays in any of the above styles and feels like hooking us up with a score or a recording that we could use, you would be the coolest person in the history of the world.

• I may be abusing the phrases "public domain" and "creative commons" here- I have tried to sum up what the copyright issues are and our stance on them, but essentially we need music we can put in a derivative work and potentially show in public.