Whats wrong with clay? Santa Clara Valley was famous for it's cherries and apricots and it's all clay soil here. Holds nutrients and water well, just need to make sure it can drain.

Peat moss is acidic, some people grow just in that.
Azalea mix is acidic and can be used.

Here is Dave Wilsons take on it....

Here is a link that might be useful: Blueberries in pots

The recommendations I've seen are in the range of 4.5 to 5.5. In some conditions higher will work but I'm most comfortable at 4.5 to 5. Don't think you can go wrong there.

In general clays are considered poor for blueberry. But all clays aren't equal, some are awful for almost anything some are quite good. A soil is called a clay with anywhere from 40 to 100% clay. And there are several types of clay minerals. There is a huge variation in clay soils.

From what I've read,Rabbiteyes are more sensitive to pH and like it a lower than Highbush.
I mix some moss peat with Pine bark mulch at about a 70/30 ratio of Pine bark to peat.Brady

To melikeeatplants: Did you say the clay needs to drain? What is that? Whatever drain means, it doesnt happen with our soil here.....(ha ha)
I grew yellow/orange raspberries for a client about 6 years ago, in horrible clay at her home which used to be a rock quarry next lot over, and even though the soil is flat out terrible, those raspberries tasted better than any raspberries I've ever had! I grew the same variety in good organic soil at my house, and they werent good at all. In fact, they tasted completely different.

But I dont think blueberries like it, because half mine died in clay.

To fruitnut: You say that the definition of clay soil is any soil that is 40%-100% pure clay? Well, ours is 400% pure! Actually thats not completely accurate, as we also have rocks and roots too....The name of the type of clay we have is "worst"