We will be in Dublin for several days in late July, and then are looking to take a short tour (4 days, 3 nights) starting July 31, covering Dingle Peninsula, Ring of Kerry, Cliffs of Moher and Bunratty castle. I've been searching but very few tours I can find start on that particular day (we are stuck with that date to start our tour). Any suggestions?

Also we will be looking to take one or two single day tours from Dublin while we are there, One to Belfast and Giants Causeway, the other to Waterford.. Again, any good suggestions for a tour company?

1) Why Waterford - do you know Waterford is bankrupt?

2) If you must tour on specific dates - then you may need to hire a private driver/guide.

I have no personal knowledge of this company, and they are not a luxury tour, but I saw their vans all over Ireland last summer, and they offer short tours (although some are geared to the backpackers).
Paddy Wagon Tours
http://www.paddywagontours.com/tours.php

Mr. Mike, as Jansi says, Waterford crystal has fallen on bad times. Not sure what is available in crystal there now. I must say that of all my travels in Ireland, the Waterford factory complex was the most disappointing - it's just like any American upscale mall. Ireland offers sooooo much more!

MsSteinrunner: Paddy Wagon is fine for budget travelers. But their only 4-day/3 night tours leave on Sundays so won't work for the OP who must leave on Friday July 31.