I think Liberty X are indie too (V2 records), then theres Franz Ferdinand of course. Theres no real signifigance to being on an independant label (independant from what exactly?), its neither a good or a bad thing. Then theres the whole thing of continuing to refer to bands as indie despite the fact that they are now on major labels (Radiohead, Coldplay, etc.). If mainstream is a slippery concept then "indie" defies consistent definition.
Unicron is right however, to point out that Damien Rices' success outside of Ireland should not be overplayed. He's big here, but still outside of the general public conciousness elsewhere.