I hid mine in a way...
I recently went wheeling with the top off and hit a bit of mud, which ended up getting thrown on my CD radio. ÂÂ
Not wanting to let this to continue to happen, I went to a local boat shop called West Marine.  I picked up a "Radio Splash Cover" made by Poly-Planar Inc. ÂÂ
The cover will work with a twin shaft radio or with a DIN sized radio.  If you use the DIN size you will have to cut the tabs off for the twin stick radios.
Since the cover is intended for use in a Marine environment, the door is sealed with a foam-rubber gasket, the rear portion (white area) is sealed with a gasket as well.  So the mounting surface and the door are both sealed.  Stainless steel mounting hardware is included.  Although it protects the front of the radio from water intrusion, it does nothing for the rear of the radio if you happen to swamp your vehicle.
Since the cover is wider than the stock Tracker radio trim plate, you'll have to cut into the dash panel a bit.  All that's required is some careful Dremel work and the cover will fit.
I put the cover in place, used a Sharpie to mark the dash...
About 10 minutes later I had this:
The cover has two detents where it will hold itself open...
The first...
...and second...
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A couple more shots of it in place:
Since my radio came with a remote control, I can leave the cover closed and not worry about getting it muddy, even after a full days wheeling. ÂÂ
I've used these before on my Jeeps, and they work extremely well.  The cover locks closed pretty tight and can be a bear to open at times, but with the remote control feature it's not a concern.
The white frame you see has been sanded with some 220 grit and painted with black bumper paint.  It blends in nicely and your radio won't get wet if you hose out the interior.
As for the rear side panel and 6x9s:
