Once you get to Veteran street cred, there is a weapons dealer in Rat's Nest (Location of Rat's Nest is top right corner at the end of the street perpendicular to The Docks transition in the Redmond Barrens). There you can get some better close combat weapons and other equipment.

I am playing an adept also and I found when playing the SRR: DFDC game that the different knucle weapons are great they do str +1 ,+2 ,+3 damage and they count as unarmed so the killing hands are additive with them.

In the newest version you can buy +1 knuckle weapon from tier 1 vendor (beside Wyverns Tooth in Redmond).
Throwing knives and shuriken purchaseable from tier 2 / Greenhorn level reputation vendor in Downtown.

Ok I found the +1 knuckle weapon in Redmond Barrens and the +3 knuckle weapon in the Rat's Nest but could not find a +2 knuckle weapon anywhere and the skill requirement and cost for the +3 knuckle weapon is really ridiculous, it requires close combat 8 to equip.

I didnt found other fist weapon, I think only this 2 are in the game.

I can almost understand why Southwind only has the level 1 and level 3 knuckle weapon and why the level 3 has such a high skill requirement to use. Since Soka is supposed to be such a badass your character will have to be almost a god mode beast to go toe-to-toe with him in a fight. Which if true will make the ending so much sweeter.