Portlaoise, the midlands city.

I agree on the point that Ireland is too small to have a "midlands city" which is to rival other larger cities in the country.

As a previous poster stated, you need to grow the population massively to fill the services (like the universities and IT's it will have and somehow build).

A more realistic solution is to build up the likes of Cork and Limerick, both strategically South and West, both have international airports, both have large ports both in city and outside, and crucially both have the population to fill large jobs from big services.

Portlaoise simply doesnt have that availability. I would however look at places like Sligo on the north West and somewhere like Dundalk which have slightly bigger populations, there needs to be more investment above the line drawn between Dublin and Galway

When people say "We need to build up X" what exactly do they mean? Who needs to build it?

I presume the answer is "the government" but they're not in the process of building up places as it is. It's not as though the government is doing large planned settlements and cities like the Soviet Union.