Whatever it is, this sounds really exciting:
http://www.steinberg.net/en/newsandevents.html?et_cid=15&et_lid=20&et_sub=MPS%20show
But this here:
“Major product update at Music Production Show”
sounds like 8.0 to me, because “7” is the major version at the moment.
Oh, exciting times we live in! 
No 7.1 or 7.5 before?
I do not hope so!
But “Major update” really sounds to be “expensive”. 
If I’m not mistaken, Nuendo is still at v6.x, so I guess Nuendo 7 would be more likely…
Nuendo 6 = Cubase 7. There is no lag, just different numbering.
So, no. It is NOT Nuendo 7, at least not exclusively.
“Update” is not the same as “upgrade”. I would bet for a 7.5, but then it could be any other thing, like this one:
Cubase 7.5
or
Steinberg Virtual Guitarist 3
My bet is 7.5 or just something totally out there.
Both I hope!
Cubase 7 doesn’t even support Windows 8.1 officially so…
Ok, lets use pure logic and leave wishful thinking aside.
Leads to one conclusion: it’s about Cubase, for it being the most important product of Steinberg.
Possibly 8.0, but more probably 7.5. I’d say:
60% probability it’s Cubase 7.5 (because of the “update” wording)
25% probability it’s Cubase 8.0 (because of the “major” wording)
10% it’s one of the minor products which no one really cares about (because of the, compared to a new Cubase version, rather disappointing “this changes everything”)
5% it’s Cubase 7.1 (because it would be a possibility as well)
My opinion:
If it is Cubase 7.5 or 8.0 I will dance on the table. 
Groove Agent 4
Firm candidate as well!
Starcraft III
HAHAHAHAHAHAHA
I’m with TheNavigator on C7.5/8.0, was my immediate reaction
black box, pattern is a portion of the existing pattern on C7 box
Nah…Starcraft III.5 
I’m guessing the new score app they’ve been working on.
As steinberg have been quite for a while over cubase you may find its cubase 8 , with poly variaudio and a sampler.
or Groove Agent 4!
take a look at the picture of the blank box and you will see its has a circle with a line through it . this is the cubase box design .
Yea your right and if it’s true I didn’t see that one coming