Obviously most people don't start with 10 INT, or take Tag! but still, its awesome. If you dropped a weapon skill, you could probably max twelve skills by level 30.
Just thought I'd share this.
PS I used the Goodsprings glitch to level 50, then worked it up from there. They all got to a number (which I can't remember perfectly), which when all of the available skill books are used (4 in the Mojave, 3 from DLCs) would add up to something in the mid 90s.
Pwetty cool.