Plugins: writing a generic (Node) plugin

hello one and all,
i thought i would solve by writing a Cons (Node) plugin (and, perhaps, a spreadable Switch (Node Input) ). however, i got stuck right at the get-go when i could not figure out what to make my input type. i’ve tried searching from the specs, but maybe i’m missing something.
so, my question is, if i want to make a plugin of category Node (like the native Switch (Node Input) ), what should i input as the template type of my ISpread?

The Node Datatype seems off-limits, deep within the core. It is probably just a disguise for unmanaged Pointer handling, that can point to anything from a DShow-Stream to a RenderState.