Exactly, there would be more manual SR20 boxes around, even NZ new ones from SSS sentras etc would all bolt right up.
Most importers are reluctant to split engine/box combos, but I would imagine the CVT box from an SR20VE would be quite high demand, along with the engine.
You could always just drop in a less exciting SR20 and box from a SSS Sentra/ GT P10/P11 Primerror.