Hello!
My first thought was to go for a 3D print - but you say it doesn't work that well for you.. Maybe it would help to go for a professional printer? I'm using shapeways and they can print "wires" down to 0,4mm and reliefs like the dials on your radio down to 0,1mm - so I'd say you can get a pretty decent radio in 1:35. Do you have a .stl file or a render of your 3D drawings? Maybe I could help you with those.
Good luck with that radio and have a nice day
Paweł