Brett, if it was me I would honestly be buying a new remote head UHF to go with the nice new D4.
I reckon the coin tray option mentioned by Justin is probably the best, however to answer a couple of your questions .....
1. You could make a bracket similar in design as the mic bracket that Rich made in this thread.
http://www.aulro.com/afvb/l319-disco...set-up-d4.html
 
Obviously altered to mount the unit rather than mic. This location would annoy me I think.
2. Vertical mount - my Dad has done this by making a bracket that tucks into the trim edges.
However, he used the passenger side because his left leg tends to rest against the centre console.
He finds this not ideal because the controls are difficult to see.
Regards,
Scott
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