I wouldn't mind seeing some sort of in game memorial, but I do think it would have to be vague and fit in with the lore. Even if it was secretly about those we lost.
I understand what JayvirDeforte is saying too.. FFXI for me used to be a place where I hid from my real life depressions and pretended they didn't exist for a short while. When times got bad sometimes I think it was the only thing that kept me sane. A distraction. Something throwing reality back in your face may not be appreciated.
Perhaps a stone monument in some remote location. A small cave or area where people don't need to go if they don't like, but can if they would like to. A monument to our fallen adventurers.
I'm for this idea if done right.