The original call out for a marking of International Workers Day in Wales centered on a large event in Cardiff, there was a number of obvious reasons for this, but by no means does that mean anything has to be prescriptive. Indeed perhaps a decentralized, multi-topic and multi-tactic mobilization would be a better choice.
Some on a thread on urban75 have suggested for events in multiple locations across Wales, on his Red Rememberer blog Gethin ‘Iestyn’ Gruffydd suggests Swansea as the most suitable location.
Where any Welsh MayDay event takes place is not that important, what is important is that one does take place! Matters such as location, themes and tactics need to be decided upon by the coming together of people from across Wales who wish to see such an event happen. A meeting to get this process started will be called in the near future, though given the geographical area that many of the activists who have an expressed any interest live in the south eastern corner, this will almost certainly take place in Cardiff.