I must admit that I don't really have any strong beliefs on the unification of Ireland. I can certainly sympathise with past horrors committed by the British against the Irish, but that doesn't realty translate to what the future should be. Actually, that's not quite true. I believe that Northern Ireland should determine its own future.
As regards representation, I feel that NI's citizens have the right to be represented, wherever they decide they belong. It particularly concerns me that in the current situation, Sinn Fein don't represent their constituents' interests in the UK parliament. I say this from a standpoint of very much sympathising with Sinn Fein's existence, although I wouldn't vote for them purely because they don't take up their seats.
I know that SF not attending at Westminster is old hat. I also know that the problem they have is in swearing allegiance to the queen. The queen? I'm sorry, but this is my parliament. A UK voter. MPs should be swearing allegiance to their constituents, not to the head of state. So I can understand totally where SF are coming from.
My solution? Swear allegiance to the right people, and don't give SF the excuse. Make sure that all the people of NI are represented in parliament.