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Kris,
An exit pupil around 0.8-1.0mm is obtained at the optimal useful magnification of a set of good optics for a given aperture. The magnification is approximately X1 ... X1.3 per mm of aperture.
Binocular objectives however are essential fast doublets, similar to finder scopes, optimised for LOW power wide field views. The images from binocular objectives don't usually stand up well at high power - typically you'll find some aberrations.
For an 80 mm lens to work well at 100x there are only three solutions - either it must be about f/9 or longer (resulting in a long tube), use ED glass in one element (expensive) or resort to a triplet lens (even more expensive).
There's ultimately only one conclusion - if you want high power buy a telescope with good optics. Not binoculars.
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