I've worked with radios in my job for about 30 years and have quite a collection of new and old stuff, plus weird and wonderful antennae.
I'm not sure whether you are advocating some sort of business to supply airsofters with radios or whether you just want to experiment.
If its the former, you run the risk of making what interests you rather than what people want to buy. Its the old problem of hobbies vs work.
How much do you think the average airsofter will pay for a radio ? In my experience, most expect to pay less than £40 each.
How many airsofters will pay £100+ for a radio - from what I've seen, if you go the TRI route or converted PRR route, you are looking at in excess of this. PRC-343's are changing hands at much more than this when they are complete working sets.
The TRI units from the far east are not perfect but are probably the best available in the operational replica market - not cheap either. Basically Baofeng radios in a new skin.
To be honest, I don't really care what my radio looks like. Its hidden in a pouch and on a locked simplex frequency for a game. At most, I reach in and give the volume knob a twiddle.
In terms of marketing and if I wanted to go into business doing this sort of thing, I would take a Z-tactical headset unit apart, sort out the imperfections, add a volume control to a PTT so you don't need to touch the radio in battle and provide uprated headsets to work with the existing common radios. The US style dual earcup type with audio level protection (talkthough) is gaining in popularity in Airsoft.
http://www.airsoft-forums.co.uk/index.php/topic/23646-sordins-with-boom-mike/
Everything is historical that you see anyway as the military world is moving into cognitive radio and all the radios we are talking about now will be replaced with CR at some point I suspect, which means a whole range of new radio products to lust after in Airsoft.