Good thread.
I think
Dave Norman was capped for Canada while with us. A couple of years later (in 1986), he played in the World Cup.
We've obviously had loads of underage internationals at various levels for Ireland. Willie Browne was the highest capped for us, getting a B cap in the 50s. Under 21 caps have gone to Ciaran Martyn, Clive Delaney, Robbie Doyle, Conor Sammon, Ronan Finn, Gary Dicker, Conor Kenna, Ian Bermingham and Darren Quigley off the top of my head. I think the likes of Mick O'Byrne, Shay Kelly, Jason Sherlock, Barry Ryan and Tony McDonnell were capped at 21s level too. Gary Dicker's probably the highest capped of them; think he got seven or eight caps while with us.