As I recall grimmkt, the ledge looking area is not very deep and not particularly wide due to some other dash supports in that area. My Sirius head unit is roughly 4-5"x4-5" by about 1.5" deep so it was not a problem (I turned the flat side towards the firewall). Anything much bigger might get very tight in there, especially if you have the JBL system (or the Nav unit). If you don't mind fooling with the hour or so to remove and reinstall the radio, you can always "dry fit" it and see if there's room.

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2007 Tundra Limited Double Cab 4x4 Super White
Key FOB Tailgate Lock (courtesy of Toxarch)
OEM back-up camera w/flip down monitor
Sirius Satellite Radio
20" OEM alloy wheels
Line-X Bed liner
UWS Black Powdercoat Low Profile Toolbox
JC Whitney Black Nerf Bars
Lund Interceptor II Bug Shield
Tekonsha Voyager Brake Controller