So I only just tried this today after thinking about it for a while, and it works and is pretty broken so long as you don't mind waiting a few extra seconds at the start of each quest:
Apparently you can trade your weapon to a paladin, he can cast Holy Sword on it, and then trade it back and it keeps the enchantment for the full duration. Not sure if this is WAI, but it's pretty dang awesome, especially if you're a crit-based character running with a paladin.
Which brings up a similar question: can someone do the same thing with other "self" buffs that attach to the weapon like artificer enchantments? It'd be slightly inconvenient to pass around weapons each quest, but the results would be fantastic.
Also, as a side note, does anyone know why a rogue's ranged power would jump from the 20 stated in the enhancements to 50 after U25 Patch 2? Cause for some reason that I couldn't figure out, that happened.