I expect there are cartridges that can top the 35 Whelen load as described. But that is an academic issue.
In the real world of elk hunting one has to ask, "Is this rifle/sights/cartridge combo MY elk rifle, the one I shoot well and have complete confidence in?" The answer is obviously personal and not open to debate.
The 35 Whelen with factory ammo or handloads of comparable ballistics is an excellent elk cartridge. I have killed elk, mule deer, whitetail, antelope, and one mountain lion with a Rem. 700 Classic and Weaver K2.5 scope using both factory and handloaded ammo. It performed quite satisfactorily on all of the above. My longest shot may have been 125 yards on an antelope doe, shortest was about 50 feet on a large whitetail doe. I shot a spike elk in 2005 at about 75 yards and a 5X5 at 40 yards in 2005.
But other calibers work well on elk. In my firsthand experience 30-06, 280 Rem., and most recently, .444 Marlin ( a cow on 10/17/06) will drop elk with one shot.
Enjoy your quest...there are lots of great elk cartridges out there.