The JamKey is basically a 61/73k version of the DMC-122 but as AnotherScott said, it is not separable and the lower keyboard is not hammer action. If separable, the weight of a TP-40L would not be a hindrance (hint hint).
Back to the Seven, it seems fantastic for what it sets out to do...If I did go down this path, though, I'd have to add a set of drawbars (and organ module) on top which means added hassle and loss of that clean look - but that's just me.