It seems like a couple of the sets are geared towards assassins, such as the Long Shadow and Treachery. I think those are traps and not worth the nigh-impossibility of getting them.
Instead, I think the best bet would be to load up on any filigree that offers melee power. Sneak damage scales 150% with melee power;
that is the DPS of an assassin. Ideally, it would be a 'rare' filigree for the extra amount, such as The Long Shadow: 3 melee power plus 2 rare MP bonus=
5 melee power.
Next, there are some that have low-hanging fruit for melee power with two filigree in the set, so that might be an easier way to grab another 5 melee power as well as whatever the extra filigree offers (such as bonuses on damage or an ability score). The following offer a
set bonus of two filligree for
5 melee power as well as a 'rare' melee power filligree for 5 mp:
- Long shadow
- Sucker Punch
- One against Many
- Treachery
If you are able to get four rare filligree for 5 melee power from each of these sets and then whatever other three to complement them in the set (ideally a boost to Assassinate ability like Dex), then you could conceivably have
35 melee power on your weapon. That is more than a ToEE full set mythic boosted from rare Shrooms (24 max) but only on ONE WEAPON.
Thoughts?