For that race, I don't think so, but you may want to contact the organizer to find out. I would imagine it would be a much, much shorter course however which negates a lot of the toughness found on the more remote lands in the north.
Single-Day unsupported... toughest that I know of is the Hoodoo 500, "Voyager" division (formerly known as the "Maverick" division), but it will take more than one day.
Invitation only for the Voyager division. 500 miles and 31,060ft of climbing doesn't sound too bad, but it is considered the toughest race around. People who do this scoff, rightfully so, at the regular racer who aims for Everest, and Everest is not single day... in fact you get a full night's rest in between! The Hoodoo 500 is a straight shot with no pre-determined breaks in between the sections although there is an opportunity to legally check into a hotel (you're still timed though), the majority of the route is at a high altitude, and you hit 10,600ft elevation at miles 255 and 407.http://hoodoo500.com/
Everest is technically not supported, but having people/family/friends/whatever hand you bottles is support. Voyager division = you're on your own for support. Period.
Of course there is working with other racers along the course, and people I ride with can rattle off many stories about how they helped other racers who were coming down with serious health breakdowns in certain areas (like getting hypothermia at 10,000ft at 2am), sometimes racers would work together for certain stretches, etc:, but that's humanity and racing. Outside of them you are on your own.
I'm not at the capability to be there yet (circumstances limit my ability to train for those events at the moment), but I do ride with friends who are at that level. Both Tour de BC and Hoodoo are personal goals.
For those that want to race your own personal clock and make it really challenging, there are a few very small bunny-hop supported good ones:http://www.inyoultra.com/
Temperatures for both the Sherman Pass and Mt. Whitney editions hovered above 115° F.
Single-day, no breaks.
|| Other projects in the works.