I took this idea one step further and built a full 50 card deck. It's a lot tricker as it's harder to see your key cards, but it's actually a very solid deck. Like all things in this game (for now at least) it is dependant on luck to an extent: a horrible draw from the shadow deck or your own deck will undo you, but I think it is fairly consistant.
The basic premise of the deck is simple: utilize spirits amazing threat reduction to keep yourself under the radar while questing with their powerful questers (Eowyn, Northern Tracker and Lorien Guide.) Discard all of your 'out of sphere' guys to fuel Eowyn's ability, then bring them into play with Stand and Fight. Use Dwarven Tombs and Will of the West to get your Stand and Fight's back. Dwarven Tomb can also be used to re-use Galadhrim's Greeting. The most powerful part of this deck is that you have more control over the game than with any other deck I've played. You keep your threat low, snipe bad guys with Dunhere, avoid nasty cards with Eleanor, Test of Will and Hasty Stroke. I beat the second scenario fairly easily the first time I played this, though it (barely) beat me the second time, mostly due to the second Hill Troll cropping up right at the beginning of quest 2 right around the time I ran completely out of cards due to not seeing my Gleowine.
The most obvious shocker is how many out of sphere guys are here. Honestly there isn't much else to fill the deck up with and it works pretty well. Even if you only see 2x Stands and 2x Tombs, that's 4 very powerful guys you can put out. Gandalf is also essential for his threat reduction and utility. All these guys are getting discarded to Eowyn anyway, so they are serving another purpose as well.
Heroes (not the greatest combo, but damn it's nice to start with such low threat)
Lorien Guide x3
Northern Tracker x3
Wandering Took x3
Out of Sphere Allies
Gleowine x3 (Yes he's unique, but it's worth it to find him.)
Faramir x3 (See above)
Daughter of Nimrodel x3
The Favor of the Lady x3 (All goes on Eowyn)
Unexpected Courage x3 (All goes on Dunhere)
Stand and Fight x3 (Key)
Dwarven Tomb x3 (Key)
The Gladhrim's Greeting (Key)
Will of the West x3 (Allows the deck to theoretically work infinitely)
A Test of Will x3 (Always nice to have 1 of these in hand + 1 extra resource available)
Hasty Stroke x3 (Same as above)
Light in the Dark x3 (Kind of useful to buy yourself an extra turn to reduce your threat or get rid of a guy once your threat is reduced below his level...but I certainly wouldn't have 3x in here if there was a better card available.)
* Allows you to utilize several very powerful key characters from other spheres without having to worry about the resource crippling dual-sphere decks suffer from.
* Spirit threat reduction buys you much more time than most decks, allowing you a few extra turns to get your combo's in place. Once you have a strong established base, you can theoretically reduce your threat forever and be untouchable while still dealing with threat buildup through your awesome location-killers and Dunhere.
* You start out with an awesome quester right away, ensuring you won't suffer from any early game threat bumps.
* Like all decks that are not Lore, this suffers horribly from a lack of card draw. Gleowine is very necessary, but the deck really needs something else. This game could really use a neutral Gleowine-like character.
* If you get a crappy draw, you're in trouble. The mulligan rule helps that a lot, but sometimes you'll end up with a hand full of out of sphere characters and nothing to do with them. Though you have a few extra turns to deal with that because of your low threat, it can still kill you if the shadow deck gets a good draw.
* The deck is fairly expensive. This isn't that big of a deal - 2 turns is worth a Beorn, and this deck isn't putting characters out as fast as other decks, instead relying on fewer, more powerful characters. But it is still expensive, and honestly only Leadership has a great resource engine.
* Swapping Eleanor for Aragorn. You lose a major advantage (your starting low threat) and you are open to a turn 2 Troll attack unless you draw well, but you gain a major resource boost with the attachements he can bring in. Aragorn works best here because of his 'gain the spirit icon' attachment, but theoretically you could bring someone cheaper in just to unlock Steward of Gondor + their 1 resource guy.
* Swapping Eleanor for Berevor. This is a more viable option in my mind as your threat isn't nearly as bad (27) and Berevor singlehandedly solves your card draw problem. She can also purchase Gleowine turn 2 'honestly', and makes Daughter of Nim make more sense. But your Spirit resources take a pretty sizable hit, as it now takes a solid 3 turns of production to get Beorn out, and it makes it much harder to 'save' a couple resources for your cancellation cards.