There is a lot of speculation but no official word as this time.

The only reason the ti doesn't make sense right now is because the GTX980 is completely unlocked already, unlike the GTX780 (where the TI was the "full" version I guess).
 
At the same time I could see something being released to fit the $700+ budget range. But perhaps it will be a Titan 2 or something similar.

We wont see the GM200 till after AMD releases there new top card and it would have to trump the 980, and from the rumors it does by a small amount. The GTX 1080(they have to use this name lol) will then be released some time Q1/Q2 2015 and kick AMD's but again and Nvidia will rake in the cash once more.

Dedaciai
.I bought a 780 and two weeks later the 780 Ti comes out. Doh!

No offense, but that was your own fault.  R9-290X was not just rumored to appear around that time, but that the leaks available implied being as fast as or faster than GTX780, but $100 cheaper.  This mean that both GTX780 and the first Titan had to be succeeded to prevent loss of sales.  A GTX780 Ti was an eventuality.
 
The circumstance right now is different, there are no rumors of an R9-300 series appearing in the next few months.  nVdia has no incentive to bring something else in, even the cheaper GTX960 that was to appear this month has been postponed to next year.
 
That being said, nVidia didn't have to debut GTX900 as cheap as it came, threatening their own Titan Black and higher-end GTX700's unless they thought AMD was supposed to come earlier; and because it hasn't yet, GTX900 supply drained away too fast because it was too cheap.
 
The lesson to learn from this is that you have to research online for rumors from both sides to get an idea of their next steps.  

New versions and variants will be released periodically over the next 6 months. I expect TI variants to be released between March and April 2015.
 

My guess would be no Ti version at all. The 780ti was a last minute answer to AMD dropping very competitive cards after Nvidia had already dropped the 6xx refinement, which was the 7xx series. If AMD drops very good cards then nvida will probably lower prices on this round of cards, eat some crow for a bit and then drop the refined version of the 9xx series which will be a new naming scheme of some sort. GTX1080?!?!? 180GTX?!?!? GTX180?!?!? Who knows, but that's the series you'll see a top tier TI on most likely, if they even do a Ti again, and Kingpin cards from EVGa too.
 
Edit; Just saw the other post about a 990. That is a card that we will probably see, imo. Def a wayyy better chance of that then a Ti version this go around. 

aka_STEVE_b
Not too sure about a Ti version , but the Classified should be soon - &  since these new card cores are so cool / efficient , I could very easily see a dual-core version card.....
 
 

I agree I would love to see a "990"

Can we assume that the yet to be released little Maxwell (20mn) will have it's own drivers, that will be unfortunately not compatible with big Maxwell (28nm)? I have 2 Evga GTX 970s that work really well for me, I would hate for them to be rendered obsolete in a few months.

Since the 980 GPU came out fully unlocked I don't see the 980's refreshing outside of a voltage boost/mem upgrade to reach a Classified version which IMHO says that the current 970's are also about fully fleshed out except for a similar line of reasoning as the 980.
 
Makes more sense if Nvidia was going to do anything w/ the current Maxwell GPU is to come up w/ a dual Maxwell GPU R9 295 2x killer...............................& make it a double option, 1 on air cooling & 1 on liquid cooling.............
 
As I see it, it will be when the Maxwell GM 200/210 GPU's come out will there be an option for a Ti class but most likely will definitely be a Titan refresh.
 
My 2 cents............................................
 

VVhiplash
Why does everyone keep saying that the 900 series isn't the full maxwell series? I know the 760 was the first maxwell to come out, but I thought this was the full maxwell series now? Whats the difference between all these gm200/gm210 stuff? I'm a little confused :P

First off, GM210 would be the refresh of GM200, but we don't know which would appear first.  With nVidia codenames, the smaller number is the larger die, GM200 is bigger than GM204 and bigger than GM206, etc. Hypothetically, a refresh of GM204 would be GM214, but we don't know if it is coming since most of any idea we have is based on leaks and rumors.
 
 
With regard to the big deal people are making, many disregard nVidia is a business and competition sets the tone of progress, they don't make stuff just because we happen to like them.  Just like with the introduction of Kepler, nVidia is again putting what could have been a midrange GPU (GK104/GM204) into a high-end model branding (GTX680/GTX980) just because AMD's best (HD7970/R9-290X) happens to match up to it.  So until AMD is within months of having something close enough to nVdia's yet-to-appear champion, we either won't see it anytime soon-- or if we do, they'll overcharge like they did with the first Titan (because AMD couldn't do anything about Titan for almost a whole year).
 
But this time the transition from the 28nm to 20nm is upon us, and while the power levels of the high-end Maxwell is low enough that nVidia could still bring a GM200 at the 250W range as the first Titan but twice the performance, there aren't enough rumors to imply anything AMD can do.  So whether something better that GTX980 comes from here on out highly depends on what AMD does about it, because nVidia already made a move with GTX970/980.
 
Regarding GTX750 and GTX750 Ti, nVidia decided to drag their feet with mainstream and gave AMD the GTX650 Ti market and didn't have anything else but a random Maxwell GM107 GPU that worked out so well-- and gave the rest of us a preview of what high-end would like.  It was a $150 65W card with half the performance of GTX780.