I've never tried, (and wouldn't want to) but it might be possible with MMs. As stated above, all you'd have are lvls with no skills.I know that when the level cap was raised from 50 to 60 several characters did the 10 lvls in less than 3 days. One character I know did it in that time by 4 botting.
Remember, zones and gear were very limited at that time, so it was quite an achievement.
Today I'd guess you could get to 60 in a week. One to two days in Glooming Deep and Paludal to 20-22. Then a day or two in DSP to 50. Then I'd try Dranik's Scar from 50-55 for a day then maybe Bloodfields to 60. By "day" I mean 12-16 hours, and of course we're talking power leveling. I wouldn't try it, but I'm guessing it could be done. These would all be yard trash kills, with nothing special regarding raids, gear, etc - and no time looting.
I don't know the lower limit for the Forgotten Halls, but I guess I person could go from 20 to 53 right there, with a 10 minute break every six hours to reset the instance.
I know that with a steadfast servant, good buffs, and a butt load of potions, I can solo a yellow bubble in DS in half an hour for a mid 50s character working alone on faction. So 2 1/2 hours a level, providing your healer/buffer could keep up. You could go faster if you killed Dragorns as well.
And the point of this would be...?
If someone was willing to do this, they'd proably just buy an account, and be a menace on the server for 6 months while they learned the game.