A tonfa-blade style would keep the hand occupied, fitting more with the rules.
http://www.tonfa.org/tonfa-blades
Milspec article about that version of Chimera, say: "sword"
And, because
Independent Weaponry made in before introduction of
Celestial series, the first five prototypes definitely had
No-Dachi-style swords. But... IW plant been destroyed, and new
Chimeras been made some time later, close to the end of Jihad, and by
Kressly Warworks, which, as former blakist plant, could use fixed Retractable blades instead.
I have no qualms about type of handheld weapon, but, I suppose, it need some refining, and detailing -
Just make it prettier, Stinger, please.