As well as Mike O'Connor, as Cats has already said, I can put you in touch with a Cornish piper, Rob Strike, who is also a Music teacher at Launceston College, N. Cornwall. He plays a lot for Gorseth events and the like. He made his own set of Cornish pipes, and is a friendly sort of chap who I am sure can help you out.
Lamorna, White Rose, Trelawney, Camborne Hill, Bodmin Riding, come to mind readily as those The Cornish love to sing.
Mike O'Connor has published several books - one named This Song Sing To You may be worth investing in - and Fooch, which is a book of Cornish tunes, with CD. Also Ilow Kernow.
Are you in Cornwall?
Cheers, Lucy