Just to shed some light on the issue of Berdych playing with an unstencilled Head but still carrying a Dunlop bag:
In a recent interview with a Czech newspaper Berdych said he couldn't stencil his new racquet because he was still under a contract with Dunlop and that formal issues were being resolved.
As for the reason for the change, he said: "The new racquet is better than the previous one in a number of things. The reason for the change was a problem in the design and manufacturing of the previous racquet. It was no longer the same."
This reminds me of what Blake complained about - Dunlop not being able to supply him with racquets of the desired specifications any more.