Can you create a weapon focus out of something like Hardliner Gloves or any other similar item?

As a GM, I'd say that's fine.

EDIT: To be clear, I believe these are "weighted knuckle" gloves? In which case, you're not actually unarmed - the gloves are the weapon you're fighting with. Enchanted sword or enchanted brass knuckles - magically speaking, I don't see the difference.

They're called Hardliner Gloves in 4E and Knucks in 5E. I think the general consensus is that they're okay to turn into a weapon focus that could be used by an adept (or a magician, I suppose) with the Unarmed Combat skill. Most GMs will say yes, as they're not unbalancing nor do they contradict the logic of the gameworld.

A shock glove is a dicier proposition, fluff-wise, since they involve highly-processed, technological components that would be difficult to enchant. More GMs are going to say no to that.

To me, it is less the high-tech (since you can have monofilament whips as weapon foci), and more that it deals damage with electricity - it's a touch-delivered energy attack. It may use melee rules, but I don't see an enchanted set of shock emitters bypassing critter immunities like other weapon foci. I could see it in SR3, where shock gloves do damage from impact and electricity, but not for SR4 or SR5.

As Glyph says, the technological aspect shouldn't be an impediment since there's a precedent for highly processed devices being legitimate foci:

You might as well get dikoted cyberspurs made into foci as long as you implant them after enchanting and dikoting is completed:
taking a Talisman geas (MitS.32) to offset the Magic loss (the talisman is the focus itself).

Bodak and Glyph both make good points. I wasn't trying to say, "no, definitely not a shock glove." Bodak's citations prove that a shock glove is possible to enchant, but Glyph also has very reasonable logic that electrical damage, rather than kinetic damage, might not be completely compatible with magical enhancement.

I would agree. I certainly wouldn't have any issue with pretty much any weapon being made into a weapon foci, as long as you can hit the target number. Got a character concept where you really have good reason to have a bullwhip weapon foci - sure. A monowhip foci? Sure - just be prepared to sink a lot more karma into making that thing enchanted, or paying a lot more cash for someone with the skills to make it for you.

If it is for an adept, why bother?
You can get the same result just using adept powers.

Weapon foci add dice to your attack roll and don't cost any power points, plus weapons such as the monofilament whip let a high-Agility, low-Strength character do decent damage.

And I don't know if Reach works the same way in 4 and 5e, but in 3e it's a large influencer in combat - you do not want to take on a troll with a spear, if you can help it...

Did that in 2nd Edition...

If you want to do it in style:
use a cyberhand/arm as the focus.

In SR4 it is either a bonus to attack or a penalty to the defender (attacker's choice). In SR5 it is either a bonus or a penalty to the defender. Reach still matters, but not nearly as much as it does in SR3, where it affects TN's.

The Attack Of Will in 3rd ed benefits from reach bonus. I seem to remember reach doesn't apply in this contest in 4th ed, but it has been years since I tried 4th so I may have misremembered.