TomD seems to me to be on the right track. If this tent is destined to be used for high altitude mountaineering, then Becky is looking for a different animal than just a "4-season" tent. Under Denali conditions, a tent is more than a tent; it is a matter of survival.

Even if Becky is not going to be summiting Denali, then it would be worth contacting local guides, as TomD suggested. They can give her the skinny on the worst case scenario her tent would have to withstand.

Of the tents mentioned, the Akto may well be able to withstand Denali weather. I can't vouch for it other than by reputation, though.