I would turf the radio and the heater controls. The controls can be put on the underside of the dash. Many headunit companies make marine decks with small wired remotes that have buttons and a LCD on them so you can still see your normal display information. We use the Clarion alot cause its only 2" round and controls the deck, 6 disc stacker, iPod and Sirius all from it and all you see is a nice little round controller that fits nicely into consoles on the floor or overhead.
Here is a
LINK to a picture of it.
Kenwood, Sony and Pioneer all make a version also.
Dakota digital also just brought out a digital controller for the Vintage Air GENII systems, it's small and could be hidden as well.
I like the last layout.......the one with the 8 gauges....