Looks like I'll be testing out 700c x 42 (42-622) Conti Top Contact tires on my Alaskan trip, mounted on the Rocky Mountain Sherpa. I just got the tires today. These are the best model in Continental's Contact line of bike tires and the Top Contacts are "handmade in Germany". Not only does it say that on the box but it's also emblazoned on the tires in colored lettering.

My source for the Top Contact was Bike Tires Direct for anyone wanting to give them a go.