So, when I read all this I see that you already have projectors with a MSRP that comes in around $35,000, not including the required lenses for them. Especially with the WX9211, this is far more in line with where you need to be as 3 of these projectors can hit about 25,000 on-screen lumens, which is exactly where you want to be for excellent presentation.
Now, with a 27x11 screen size, you aren't working with a standard aspect ratio, and the proper setup really requires that you use edge blending to seamlessly join 2-3 projectors together into a single image that covers your background accurately.
The 9211 lists this as a feature of the projector. With the price point and the light output, it is NO surprise to me that this projector does so. As well, it features HDBT input, so it can handle long run video transmission over category cable.
Now, if you were to get three of the ultra-short lenses for the 9211, you still need about 14', lens to screen, to fill the height of 11'.
I can promise you, that you aren't getting 3 of their ultra short lenses for anywhere near $3,000. You also need twice the distance that you have to actually get the 11' height that you are after.
There's nothing wrong with wanting to do this, but you really should take the 3 9211 models you have, make sure they are setup for a proper edge blend across all 27', and then run an image to them.
Total price: FREE
The options from there aren't pretty. I mean that they are downright ugly in terms of cost, because the reality is that you almost must use Panasonic projectors with their uber pricey ultra short throw lens. Their lens can hit that 11' height from just seven feet away. This still doesn't actually fit your needs, but it's about as close as you can possibly hope for in this situation.
More realistic, overall, if the projectors are completely hidden with rear projection, would be to do a pretty intricate setup of 6-8 or so projectors all edge blended and color matched to handle both height and width across the entire space. These projectors could be dimmer overall (5,000 lumens or so) while still producing an amazing image due to the quantity in use.
I don't really see any good options here beyond the very good projectors which are already owned, paid for, and delivering 8,500 advertised lumens.