Unfortunately, they only drop in Tyria (mainly in southern shiverpeaks and ToPK), not inscribable, so the chance to find a decent one are realistically zero, also because there are not so many players in such areas.
If you want a confirmation, check on guru, there are 21 crystallines, some of them perfect and inscribable, and only 2 raven staffs and of course with crappy stats. So, if a perfect crystalline could be worth 4-5 millions, a perfect raven staff should go for 8-10 millions, because it's much rarer!

So, my suggestions are:
1. Now that from HoH chest is possible to get inscribable items from all campaigns, even some that were not inscribable before, like
mursaat hammers(P)
gothic swords(F)
gothic dual axes(F)
broadblade swords(F)
why not adding inscribable raven staffs to the list of possible drops of HoH chests?
The same can be suggested also for summit axes and summit warlord shields (I have already 2 perfect summit axes, so I'm not speaking for myself in this case) and in general for campaign specific items, which are not available in inscribable form in that campaign.
A.net has already done this for the skins I listed before, so there should not be huge difficulties in adding some other skins.
2. This second suggestion will maybe arise criticism: now that hard mode is coming, could it be possible to get inscribable weapons in Prophecies and Factions, but only if you choose the hard mode?
I realize that the inscription system is considered by A.net an incentive for old players to buy NF.
But anyway, NF has been out since October 2006 and I don't think that there are so many GWP and GWF players still undecided about purchasing NF. Instead the possibility to get inscribable weapons in P and F playing in hard mode could be an incentive to NF only players to buy a previous campaign, because they could have the possibility to get items comparable to the NF ones.