I found me some radios that closely resembles the ones from the cartoons, it’s almost uncanny.
http://ghostbusters.wikia.com/wiki/Radio/Animated Here is a link to the Wikia page for reference.
This is a Realistic TRC-215 Transceiver which matches one of the RGB radio models.
After a quick mod, it is the spitting image of the radio.
This next radio is a match for the EGB radios, but it has one extra knob. This is a Motorola Saber II without the bottom battery.
It is pretty close in size too.
And here’s a comparison pic to the Motorola MT-500:
