FOSS gamedev and creative worlds

simple question:
Is possible to make that a 3d model (aka .blend file or .x file) be used like a node like when we are using a nodebox?
can i use a .x file instead a nodebox?.
you can't use a nodebox for things like minecarts or moving objects, but is possible for 3d object be nodes?

simple answer:
No.

It would be a nice feature though.

It is possible to use an entity with no selection box (or whatever it is called, or a really small box) and put it at the same place as the node.
In this case also make a less-detailed nodebox for the real node.

I'd love for this to be implemented upstream.