Have no experience of them myself but have seen a few threads here about www.beds.ie and they appear to have good reviews. You should run the search option on the main page and you will get the previous threads there. You might get some other info on www.furniture.ie and you might be able to compare prices there.
If you are in Dublin Kellys on Long Mile Road might be worth a try. Don't appear to open on Sundays any longer.
There is a furniture shop in athboy, meath Murphys that normally has beds in stock. If you live nearby most times you have the bed the same day (sometimes he arrives with the order just as I arrive home from the shop). I have found the beds to be good value. He delivers to dublin. He does not open on Sudays but the phone may be switched to his house. No relation just a happy customer.