Necro quest is already done on PEQ. Monk is close to completion. Check here to see the full list of what quests work and don't work on PEQ:
http://projecteq.net/quests
You can see the status of the Epics near the top. I am waiting on a member to hand me the mostly complete Monk epic, and I just started on Berserker. As for Beastlord, Paladin, and Shaman I am not sure of the status of those so if you want to work on those, go for it.
If you want to help out with quest writing, the best way is to join the PEQ Quest Team. Check out our forums
http://projecteq.net and drop me a PM there.