You can see some of his instruments here

He's on Facebook

Gordon Bok's words regarding Apollonio 12-strings (Nick's address is out of date as listed. I'll find out how he wants to be contacted these days and post it to this thread.)

Listing in the Blue Book of Acoustic Guitars

And finally, from this site:
Nick Apollonio and Kristin Tescher
"Scots/Irish/Breton/galician songs & tunes on cittern, harp and fiddle
Nick and Kristin play a unique combination of 10 string cittern and Celtic double harp, as well as fiddle, mandolin , and 12 string guitar for a rich combination of songs and tunes from their native Maine as well as from Scotland, Ireland, Nova Scotia, and Galicia in Spain. They have recorded on over 20 CD's , as a duo and with other musicians. Nick is the maker of the instruments having started more than 46 years ago and counts as his customers Judy Collins, Noel Paul Stookey, Gordon Bok, and about 800 others less well known. Kristin has played across North American and in 1983 shared a concert bill with Andy Irvine at Galway University."