I have heard that Garrett is working on something to replace the GTI series. That's no rumor. Vaughan Garrett is in a video from the AT Pro release saying, pretty much, that you haven't seen nothin yet. I also know First Texas(Fisher and Teknetics) has some stuff in the works. Don't know anything about Tesoro or the others. I say there'll be something come out in the fall. Just don't know what or from whom. It makes sense someone would push something out, with the new Minelab. With the recent release of the AT Gold, I don't forsee Garrett being the one to release anything yet. Maybe in the spring or fall of next year. Same with Whites. They had the Vx3 come out last year, I think it was. Tesoro could surprise us, but I don't remember the last time there was buzz about something new coming from them. Doesn't mean they won't have something.
Out of the big 3 of First Texas, Whites, and Garrett, my money would be on FT. They haven't come out with anything new since the G2/GB like 3 years ago, outside of a few programing changes and the return of the SE. I know I'm no expert on FT, but that seems to be a long haul for them.
With all this being said, I don't "know" anyone or anything, nor am I saying anything difinitive. As John put it, they'll come out with it when they come out with it. Garrett may pull an ace out of their sleeve.