Is there a main site or board on the net where Irish trad backup guitarists tend to hang out?
Maybe to start:
http://celticguitartalk.com/phpBB/
Kevin Krell
Nice … thank you, Kevin. Any others?
Bump … I’m still looking. 
I’ve been reading Celtic Guitar Talk for a few days. Some nice discussion, very cordial, but very fingerstyle DADGAD oriented. Irish backup is underrepresented.
I’m wondering the same thing. Subscribing to the thread and hope there are more answers.