-- Last Updated: Mar-01-13 9:18 PM EST --
I'm not sure how much bigger the 12 is, over the SP, but, it might leave some growing room, without being overly huge. I happened to notice some 2011 models available at Mountainman Outdoors, for $599.
Edit: I see those Tsunami 12's have gone up to $700, if anyone was interested.
Also: I see Appomatix River Company has a used Perception Carolina XS, for $325, if that sounds interesting, for a small paddler.