Is your question about bringing bottled beer to high altitude, or bottling I beer at high altitude? The bottling process, with priming sugar calculations might change as with the reduced atmospheric pressure, there will be less CO2 retained in the beer at any given temperature prior to bottling. Once it's in the bottle, the atmospheric pressure has little impact since the bottle is closed off from it. I seem to recall that there is something about this in "How to Brew"