It's a big number of hero points!
Colin's first post:
Unlocking your elite spec is a training line in your training panel that costs hero points. You do need to have trained all the existing training lines before you’re allowed to put hero points into your elite spec.
If you’ve got all the hero points in the existing game you’ll have enough to train about half the elite specialization training line on launch day. The rest you’ll need to earn in the jungle or via the new system Tyler outlined yesterday from WvW. The number of points to fully train your elite spec is higher than other training lines – but hero challenges in the jungle are worth 10 points each, so it’s not actually as big as it appears.
Colin's second post:
It’s 400 points total to unlock everything in an elite spec training line – I just can’t remember off hand how many points folks have currently if they have done all the existing ones, but it’s right around 200. The rest you’ll need to earn in jungle to unlock the deeper skills/traits/etc. in the training line.
You only need 60 hero points to begin using your elite spec, the points you spend after that continue to unlock more skills, traits, skins, etc.
Again, hero challenges are worth 10 points each in the jungle. So no you don’t need to go do 200-400 jungle challenges.