I like playing sneaky characters, and Mr. Scruggs' "Thieves' Arsenal" is one of my all-time favorite mods; I find the blackjack, and gas arrows to be invaluable tools. However, the unconsciousness effect they render are only temporary, and on many an occasion I have found myself killing NPCs simply because I can't afford to have them wake up and raise the alarm. This unneccessary killing usually goes against my characters' ethos. As Armand Christophe says "We may be thieves, but we're not murderers."

I would like a mod/mods that allow my sneaky character to neutralize NPCs without actually killing them. I imagine sneaking into a "dungeon" populated by bandits, catching them unawares one by one, whacking them on the noggin with the blackjack, dragging their unconscious bodies to an out-of-the-way spot where they won't be discovered by their fellows, then binding and gagging them, relieving them of their valuables....rinse, repeat. This would allow the stealth-based character to "clear" a "dungeon" - and reap the rewards of the feat - without actually killing anybody.

Is this scenario possible with current mods?

While I think that scenario would be great, I don't think there is a mod that makes it possible. What I would do is use a uniform mod that allows you to pose as a bandit, and try to sneak through and steal things. I think that is your best bet. If I'm wrong though, I'd like that kind of mod too!