Sian,

Cardiff Council may well be doing something, but they have a habit of keeping these things secret until the last minute. At this late stage I would say they aren't.
Danny KilBride or Sian Fiddle may know something.

Llantrisant have Blake's 3 on Wednesday 2nd, not parrrticularly Welsh but a great band.

I do know that there is going to be a Celtic Festival in Cardiff in early September. No acts booked yet, but there are rumours of some pretty big names.

Splott Man