Has anyone heard this rumour as well? Or has anyone seen him testing Callaway gear?

I've certainly not heard this myself mate. In fact, there's some recent pics on here of him testing the new Bridgestone driver. That being said, he was also testing (and playing?) a Taylor Made driver. Maybe he also tried a Callaway and the rumour started from that?

Apples has been with Bridgestone/Precept since the early/mid 90's and it would be a huge surprise to see him leave. I know they're meant to say it, but he's often commented on how good they are to him. They even give him a supply of tyres to use on his racing cars back in Australia.

Time will tell but I would be shocked if he left them.

I may be wrong but I believe he is in some way "married" into or connected now to the Firestone / Bridgestone family. Something was mentioned at Firestone a few weeks back about the demands on his time due to his commitments and family ties. If that is the case......he's a lifer at Bridgey.

Doesn't seem like she has any ties to Bridgestone/Firestone.

As I said......"I may be wrong," but I do know that there is some sort of connection that runs deeper than just the standard endorsement deal.