While grepping, I've found
in  base/node-ini.lua
....
--[[ldx--
<p>Serializing nodes can be handy for tracing. Also, saving and
loading node lists can come in handy as soon we are going to
use external applications to process node lists.</p>
--ldx]]--
....


\starttext
\setbox100=\vbox{Hi}
\ctxlua{io.savedata('vbox.hi',nodes.serializebox(100,true, true))}
Box reuse:\blank
\box100
\blank
\ctxlua{initt=loadfile('vbox.hi');initt();tex.box[100] =
nodes.FromTableToNodeButItnotExists(t)}
%%actually an empty box, of course
\box100
\stoptext

I was not able to find a "table2node" function ie
nodes.FromTableToNodeButItnotExists(t)


-- 
luigi