Just wondering...

The gamertag "Bullfrog" does not exist, but I'm unable to change my tag to that--so I'm guessing that means that it is being used for Zune, or another Microsoft program--is there any way to use it for a GT?

Thanks.

It means the tag has been deleted by ms which means the tag no long exists and won't ever be again.

It is probably spaced out or deleted

Either it is being used for another miscrosoft program, or it is "deleted" and unable to obtain.

I know of tons of tags that were owns by hackers and whatnot that have been permanently deleted and cannot be obtained by anybody.

It could also be spaced out as "Bull frog".

EDIT: It is spaced out: https://live.xbox.com/en-US/Profile?gamertag=Bull frog