Some of the console manufacturers make "wedge" mounts that go under the dash board on the transmission hump. They'll have 7-10 of radio space, depending on the model.
It sort of takes away foot space from any center bench passengers, but that might not be an issue.
CC-C04 Bench or bucket-seat console | Troy Products
CC-C05 Bench or bucket-seat console | Troy Products
Chevy Silverado Radio Consoles | GMC Sierra | Public Safety Source
Short of that, I've always had bench seats in my trucks, and I use remote head radios. Having to mount the control head only makes life easier. Not having to support the full weight of the radio simplifies the installation. I've almost always had to fabricate my own brackets, but that's not hard to do using aluminum stock. I also do a "through bolt" install, no sheet metal screws. I'll usually put a backer bar on the back side of the panel and run the bolt through the radio mount, through the dash board, through the backer bar and put on locking nuts. That works well with trucks that go off road or are subject to a lot of vibration.
Mounting the RF decks behind the rear seat is usually pretty easy. Some creativity required, but the aesthetics are not as critical if they are out of view.
Really comes down to how many radios you want to mount and how much you want to spend. For one radio, just putting it under the dash can work.
If you are adding several, one of the wedge type consoles might be a good idea.