The reality remains that moire patterns on microperf screens is an isssue. Stewart is the one company that is battling this and is truly in touch with keeping on top of the technologies available to them.
STEWART FILMSCREEN - Microperf X²
But, that said - they are pricey, and for the most part... pointless.
Seymour figured it out. Woven screens look fantastic and perform well with superior audio performance while still delivering a screen material that is ideal for full detail in the resolutions which people are leaning towards.
At a far better price than others, and the option of prefab or a welcoming attitude for the custom/DiY setup. They aren't just a breath of fresh air, they are the Carada of acoustically transparent screens. Good attitude, a focus on direct sales, and a level of performance which isn't just exceptional, it is superior. They are who should be used.
If you want Stewart -then buy a logo and put it on the Seymour screen, it will serve everyone better.
I'm not sure if I missed it, but screen size continues to be based upon viewing distance with a bit of viewer preference. A middle of the theater look is achieved with a screen width that is .66x the viewing distance. So, at 12' viewing, you want a 8' wide screen in 16:9 format.
But - going ultimate... I think we would be talking about a motorized anamorphic sled and a 2.35 screen. The room certainly seems to have the width to support this and the budget to put in the right lens/sled combo to do 2.35 properly.
I really struggle with the 4K request. Not that it isn't a great concept - but the product doesn't exist. It is extraordinarily limiting to demand a product that is only made by a couple of manufacturers when those products may not fit the installation that is being conceived of.
If it was a 100" to 120" screen, then a typical high quality projector for home theater with 4k resolution would be more than adequate. But, in a larger screening room - and that is what this sounds like - you need a projector with the balls to deliver the lumens on screen that leave people going 'Wow!' - whether it is in 2D mode or 3D mode.
With that in mind, I would recommend Digital Projection which is one of a handful of companies that can deliver 1080p, 3D, and the lumens to fill a larger than normal screen size with full support of pretty much anything thrown at it. I would call them and ask about what they may have as 4K offerrings coming up.
A big issue with 4K is that chip manufacturers don't support resolutions yet. So, you are paying a lot for functionality that doesn't exist and you may impact final performance due to this lack of support right now. In a few years we may see 4K really start rolling, then we will have good chip sets which support whatever 4K sources actually come to market.
Then the conundrum: Do you get a high quality 1080p 3D projector which can really deliver the best image right now on screen, or do you get one which is less money with the plan to upgrade down the road? Neither choice is wrong, but the better 1080p projector will cost a lot more today than what others may cost.
My personal favorite for a killer bright 3D performance projector:
Projector Detail
You get the lumens you need for a large screen with 3D support and the right lens for the job is available. Oh, and from a projector which is extremely quiet.
Now, if you are getting into more serious horsepower, like one of these:
Projector Detail
You are going to pay a very high amount and will have a noisy projector which is pretty much untouchable in performance. You MUST put this type of product into a projection room behind the theater. Much like commercial cinema - the projector noise is completely removed from the viewing environment. Not a bad way to go no matter what if the space allows for it.
I'm not going to go on about Runco - I've done that before. Their lack of customer support over the years and willingness to tout their products with inferior build quality and far lower than market reliability is something I don't buy into. They talk a good game, and when (WHEN!) their stuff works right it can look good, but it is like buying a exotic sports car... Drives great, looks good, but you better know a good mechanic and be ready to deal with the headaches and expenses associated. More often then not, taking a different course of action is the best decision when you only have one home theater. (most people with an exotic sports car have a second car available!)
Finally, don't forget to put in a decent remote. I typically put a basic Crestron system into any room I do - and this, as a nicer space, would demand nothing less. Make it easy enough so that the in-laws, wife, and kids can use it without screwing it up.
The rest of the design work needs to be carefully planned - lighting is often one of my biggest complaints in a home theater (not enough lighting), and the proper acoustics for everything. So, having a builder who knows what they heck they are doing matters.
All this said - Sony makes awesome projectors. They know their stuff and are in the game from better low end to commercial level high end. Their VW1000ES is certainly a statement which leads the industry:
Sony Projectors: Sony VPL-VW1000ES SXRD projector
But, just like Sony led the way with 1080p projectors out of the gate, these models will improve in performance and drop in price, likely by about 80%, over the next five years. So, you can get similar, or better specifications in five years for under $5,000. A jump from 1080p to 4K resolution does not necessitate a 10 fold price increase. It just is what they can charge being the first to market.
1080p now - 4K in half a decade and give the old projector away. It doesn't just make finanacial sense - it makes sense. We have no 4K sources and depending on screen size and viewing distance, there may be no actual noticable improvement of 4K over 1080p.