I Did A Quick And Dirty Helper Model
This may be useful to users of the editor;
http://www.quaketastic.com/files/helper.mdl
It's just a scaled up and reskinned version of Sock's voreball, colour coded to match the various entity types.
This means you can turn off 'bounds' in the model view to make your screen less cluttered. You will need to add this;
model(":progs/helper.mdl" 0)
To the various entries in your
.fgd (not sure if its the same format for .def) replacing the 0 for the corresponding skin - each skin is correctly named inside the file.
I'd share my fgd but its got modded entities inside and I can't be arsed cleaning them out.