Another solution is to have ToV boss loot drop from the named in Mistmoore.
That would be pretty EZ.
I like the way you think.
Maybe a zone that could include all the higher end Velious stuff as a whole.
Then another zone specifically for Kunark?
Or better yet, a zone with wings (obviously i mean wings like.. hallways) that could support a specific expansions loot? this would be stuff not covered already by existing custom zones though.
So one wing could have old naggy, vox, etc... original EQ loot, another wing have.... well i guess whatever Kunark had going for it? Velious in another wing with Kael, Skyshrine, ToV, Veeshan Peaks, etc.. and so on