Searched first, didn't find it. My understanding is that Penetrating strike is intended as an unarmed power, but can it be used with my trolls claymore too?

Nope sorry its a unarmed power only

Penetrating Strike
Cost: .25 per level (maximum 3)
This power allows the adept to channel the force of an
unarmed combat attack a short distance forward, thereby
bypassing the target’s armor

You could however invent additional adept powers as house rules to apply the AP to attacks with a certain weapon type.

I did this in game for a while with a phys ad (not with penetrating but I let him channel elemental fist through the weapon). Same as possessed shaman with sword, really. Not really unbalanced.

Ditto on the house rule idea. The biggest potential issue would be stacking unarmed combat Adept powers with armed combat bonuses (reach, weapon foci abilities)...but all in all I don't see it being a real game breaker. It's not like Adepts can't already be plenty scary in melee if they choose to specialize in that direction, after all.

I am ok with giving Adepts ranged strike with melee weps. makes that 1 ip worth just a bit more.

The potentially unbalancing thing about it is that a lot of melee weapons already have an AP rating, so you can have stacking modifiers. Personally, while I like adepts, they need a powerup in melee about as much as they need a powerup in social skills. Which is to say, not at all.

Penetrating Strike does not do that. Distance Strike does give the ranged attack, not with melee weapons by RAW. Again though, feel free to house rule.
Just take note that it would become a ranged attack, hence not useable through the Use Melee Weapon action, and would need houserulling further. Through losing the entire looking for an opening thing that justifies melee being a complex action, does it become a simple one? Does the weapon's reach bonus do anything?

Distance strike is already a huge powerup for melee combat, because it changes the whole dice contest from Agility + skill vs. Reaction + skill or dodge, to Agility + skill vs. Reaction (+ dodge/gymnastics only if the defender uses full defense). In other words, the equation much favors the attacker.

This is significant because melee typically has far less negative modifiers than ranged attacks (and distance strike is similar, since its near point-blank range is unlikely to get many penalties), and can have a very hefty base damage. So you combine that, with the suddenly lopsided dice contest, and you can have melee specialists who can drop even other melee specialists, or tank builds, with one shot.

I wouldn't recommend it for melee weapons. To be honest, I don't even like it for unarmed combat.