A list of ideas I've come up with thus far:
-Pair of hand guns that lock into one larger gun (Makes her mid-range, but allows for tranquility effect)
-Pair of ninjato (Bladed weapons again, but staying true to other Rain Guardians)
-Some kind of blunt instrument, like a bat (Won't allow for tranquility effect as much, but stays true to Jak's strengths)

I'm leaning towards the guns since we need more mid to long range fighters, and other Rain type flames have used guns before. (I.E. Collonello)