For starters, and to touch on your last comment, Nikon did just introduce the Monarchs in 12x42s this year.

As for why you don't typically see higher power binos...I think there are several reasons. As you already mentioned they are more expensive to make. Any mistakes in the manufacturing process are more "magnified", no pun intended with the higher the magnification you go with. When you start with a pair of 8.5x42 Swaros that are already listed at $1600 then it is very realistic to believe that you could be pricing yourself right out of your customer base should you consider manufacturing higher mag/more expensive versions of the same model.

Second, higher magnification, at a certain point, doesn't really benefit the user as much as one would think. Once you start getting above 8x or 10x then the shaking that the user transfers to the binocular under handheld conditions usually renders any gain in detail because of the higher mag. insignificant. A tripod is typically needed for most folks with binoculars in the 12 power and higher range.

Third, higher power binos are usually heavier and less convenient to carry because they are typically coupled with larger objective lenses to allow adequate light levels to reach the eye....in order to produce a relatively bright image...again so that you can actually utilize the greater detail.

One comment I have often seen made in reference to folks who issue similar questions to your own.....a moderate power binocular, 8x or 10x, usually provides all the detail that you can utilize. Going to a higher power does not necessarily give you more detail. Actually, going to a larger objective size will usually result in more usable detail as more light is allowed to reach your eye thus giving you a brighter image and more contrast.

Also, the quality of the glass and of the chemical coating applied to the glass and the prism usually are more important in rendering detail than the size of the magnification. In other words, an 8x Swaro SLC will give you a more detailed image than a 12x Leupold.

Hope this helps.