Barry mentioned Rodney Miller, and someone else mentioned
Great Meadow Music - but you should *definatly* find the
New England Fiddler's Repertoir (one and two, I believe)
by Rodney's brother Randy. There are also great resources
through the New England Dancing Master's productions out of
Brattleboro, VT. Any of these are available through CDSS.

And yes, there's Irish derivative and French Canadian music
there - as well as "home grown" New England music. The
NEDM material has tunes and dances. So, your fiddle students
could play music for each other's dancing - that way they'd
get the tunes in the context for which they were written.

Back to Bob McQuillen - he's written hundreds of dance tunes,
and has been designated a regional treasure. Most, if not all
of these tunes are available in self-published books, and many
of them would be accessible for beginning fiddle students.

Dudley Laufman (Two Fiddles or laufman.org) from around Peterboro NH also has great resources for New England fiddle/dance music,
and songs as well.

There is indeed a wealth of material out there.