I have the Gitzo bag for exactly that tripod and RRS ballhead. Its the one Gitzo recommend for that particular model.
I cant recommend it though:
A: Its too big - I mean its massive. I could put three tripods in it. Its way over sized.
B: It says Gitzo on it in big letters. It might as well say steal me when checking it in at airports.
On top of that it also looks remarkably similar to a rifle bag. I get stopped at customs all the time because they want to look in it.
I dont really know why I bought it to be honest. I think I was just desperate at the time for a bag before I went overseas a few years ago. I'm actually over it and when I get back from New Zealand next week I am going to sell it and replace it with something more practical.
You can make me an offer if you still feel inclined...
