I'd vote the Kenwood setup as described above. IIRC, not only can you do dual head, but dual RF deck to dual head. So you can have a VHF and UHF deck tied together and tucked away and have control of both of them from each control head at whatever spot you mount them. And the even better part - most of this equipment is going pretty cheap these days. The only other way I'd know is through Motorola but they were doing dual RF deck to single head with the Astro Spectras - not what you're looking for.
Now if you want P25, I know the newer versions of their mobiles can do the same - but more rare to find on the used market right now and I can guarantee parts will be harder to find cheap.
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