When I saw that this thread had been bumped I thought at long last that somebody at CDPR had simply picked up the phone and called ATi/AMD and said: "We're interested in implementing Eyefinity support in our game, Witcher 2. Will you guys send us the stuff we need to get going on that?"
To which I cannot imagine any other response from ATi/AMD, except: "Absolutely! No problem at all! We'd be delighted to help you out."
My position on this is that I know for a fact that the question of hardware support should be paramount for the developer and the publisher. While it may be true that nVidia doesn't want people buying AMD hardware, and AMD doesn't want people buying nVidia hardware, a *software developer* (and publisher--don't want to leave the publisher out) should be very concerned with supporting as wide an array of hardware as possible--not just nVidia's and not just AMD's. It's in the game developer's best interests to support "everything" to the degree that he can do so, because that will only equate to selling more copies of the game--and that's what it's all about. OTOH, leaving out a select group of people--in this case the Eyefinity people--might result in fewer sales for the developer/publisher, in this case CDPR.
There are plenty of games on the market that support both nVidia's and ATi's multi-monitor gaming hardware at the same time--which means that there's no reason this couldn't happen for the Witcher 2, too. I think, unless I am sadly mistaken, that the game developers at CDPR, the people coding the game, are as aware of the presence of AMD in the market as they are aware of the presence of nVidia. (Hint: in the absence of these two companies, CDPR probably would not *have* a business today--at least not such as it is.) I would also lay odds that all of them know what Eyefinity is as well as any of them know what nVidia Surround gaming is. If they don't know what these things are then they'd best be working in some other field, imo.
Q: So, by whatever means having obtained nVidia's help in implementing this support for nVidia hardware, why has CDPR not picked up the phone and called AMD and requested their Eyefinity support?
A: I don't know the answer, but a few possibilities strike me:
a1) CDPR is waiting on somebody at ATi, maybe the in-house psychic or resident mind reader, to "divine" the fact that CDPR has a game that needs Eyefinity support, and having "divined" that fact, to pick up the phone and call CDPR and offer their assistance. If this is the case then I think CDPR's wait will be a long one...

This is basically what the lone CDPR respondent in this thread has stated: that the support isn't there because ATi hasn't called and offered it, yet.
a2)CDPR has already attempted to obtain ATi's help in implementing the feature support, and AMD/ATi has told them to "go jump" and "never call this number again!" If this was the case, though, I daresay we'd have heard something about it by now.
a3) For reasons understood and known only by CPDR, they have not sought out AMD's help in implementing this feature in W2 for ATi hardware.
a4) CDPR cannot, for technical reasons, support Eyefinity with the W2 game engine. But were this the case, surely someone at CDPR would have stated this, or else taken the bull by the horns and picked up the phone and called ATi to get help in implementing that support.
Right now it would appear that only answer a3 above fits all of the facts as we know them. But a3 is really not much of an answer, it it?
The issue to me isn't so much an important issue as it is an interesting one. If CDPR is bothering to support nVidia's multi-monitor gaming hardware, then why not support both standards that exist? Why not support the hardware that your customers have and have asked for? Why support one and not the other?
I think we can all stop speculating, though. CDPR is the only one who knows for sure, and at the moment CDPR isn't talking. Perhaps, even as I type this, Eyefinity support is being readied for the next patch. That would be an excellent move. But do I buy the notion that the only reason Eyefinity support isn't in the game is because "Ati didn't contact CDPR and offer it"? I really don't think that's a completely honest statement *unless* CDPR reached out to AMD and AMD didn't respond. But that hasn't been said, either, has it?
IMO, if a developer wants support for a certain function of an IHV's hardware, the impetus is on
the developer to make the call and ask for such support--not the other way around. Why? Because as much as we may think of nVidia and AMD, the one thing I feel confident in saying about them both is that neither is staffed by psychics or mind readers...

IE, if AMD didn't know that CDPR had a problem with Eyefinity because CDPR didn't tell them, then the absence of Eyefinity support in Witcher 2 makes perfect sense, doesn't it?