My "elk rifle" is a Masuer/35 Whelen, but as much timber hunting as I ended up doing last year, I could have just taken my Marlin lever gun in 35 Remington, with the hot Hornady ammo, and I'm sure I would have been plenty well armed.
I'm in the middle of building another Masuer, in 6.5 Swede, and I think that would also be a totally adequate elk rifle.
And who knows how many elk have been taken in the last 100 years with a 30-30? And a boring old 30-06 should cover almost any reasonable elk hunting scenarios as well.