I hit level 60 yesteday with my shaman team, had played time of 1day and 13h. Sense iv never played horde before did a bit of running around etc, so i think if i did it again, i could push it to be around 1day. I boosted to 40 and quested from there.
Now i have 4 level 60 shamans and a gifted lvl 60 Paladin on that server