I will be taking the head of soon and do some NDT on it, probably using fluorescent magnetic powder. I will post some pics if i can.
Here is a link to a swedish webpage, you can see on the picture that is has a crack between the valves (although it does not say anywhere on that page that the head is a v4, but sure looks like it, and the whole page is v4-based.)
I have had 3-4 cracked heads, cracked twice between two valves, both were bigger valve heads, and one time crack was running on the side of the head up to the valve cover, it leaked a bit of coolant but then after some time leak stopped itself. I belive once more it was with standard valves too, cracked between two valves. If it gets hot it might crack.