Had one in the mid 90's. 6 10's in a reg cab ranger //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif. If done right, it doesn't hurt the structure of the truck much (as evidenced by the fact that I walked away after rolling mine 3X with only some scrapes and a minor concussion) but it does totally destroy resale value.
It was popular back the early 90's mid 90's. Cut through with plasma cutter then rubber boot the cab and bed.
X2-on resale value. Once you do it no going back, even if you try to weld the piece back in. You will always be able to tell now matter how good you did it.
What is you reason for doing this. Make sure it's what you really want to do. You can do ports into cab also through the bed. There many ways to do this. There is always: put something like a snug top out back and go through the window area.
If you plan to drive this everyday and keep it for a long time then I would say ok. If you could the truck up real bad the only way you are to get rid of it is generally to someone specifically wanting what you have done.